diff --git a/ra-optimisation/search-tree-rao/src/test/java/com/powsybl/openrao/searchtreerao/castor/algorithm/CastorFullOptimizationTest.java b/ra-optimisation/search-tree-rao/src/test/java/com/powsybl/openrao/searchtreerao/castor/algorithm/CastorFullOptimizationTest.java
index 236f601694..9416e8f531 100644
--- a/ra-optimisation/search-tree-rao/src/test/java/com/powsybl/openrao/searchtreerao/castor/algorithm/CastorFullOptimizationTest.java
+++ b/ra-optimisation/search-tree-rao/src/test/java/com/powsybl/openrao/searchtreerao/castor/algorithm/CastorFullOptimizationTest.java
@@ -703,10 +703,10 @@ void testThreeCurativeInstantsWithSecondCurativeHavingNoCnecAndNoRa() {
             .newThreshold().withSide(TwoSides.ONE).withMax(2500.).withUnit(Unit.AMPERE).add()
             .withOptimized().add();
         crac.newFlowCnec().withId("c1-cur1").withInstant("curative1").withContingency("co1").withNetworkElement("FFR1AA1  FFR4AA1  1").withNominalVoltage(400.)
-            .newThreshold().withSide(TwoSides.ONE).withMax(2400.).withUnit(Unit.AMPERE).add()
+            .newThreshold().withSide(TwoSides.ONE).withMax(2100.).withUnit(Unit.AMPERE).add()
             .withOptimized().add();
         crac.newFlowCnec().withId("c1-cur3").withInstant("curative3").withContingency("co1").withNetworkElement("FFR1AA1  FFR4AA1  1").withNominalVoltage(400.)
-            .newThreshold().withSide(TwoSides.ONE).withMax(1700.).withUnit(Unit.AMPERE).add()
+            .newThreshold().withSide(TwoSides.ONE).withMax(1500.).withUnit(Unit.AMPERE).add()
             .withOptimized().add();
 
         NetworkAction pstPrev = crac.newNetworkAction().withId("pst_fr@10-prev")
@@ -740,8 +740,8 @@ void testThreeCurativeInstantsWithSecondCurativeHavingNoCnecAndNoRa() {
         assertEquals(20.3, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
 
         cnec = crac.getFlowCnec("c1-out");
-        assertEquals(2371.88, raoResult.getFlow(null, cnec, TwoSides.ONE, Unit.AMPERE), 1.);
-        assertEquals(2129.22, raoResult.getFlow(crac.getInstant(InstantKind.PREVENTIVE), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
+        assertEquals(2371.88, raoResult.getFlow(null, cnec, TwoSides.ONE, Unit.AMPERE), 1.); // when dealing with post-contingency CNECs, a null instant refers to the outage instant
+        assertEquals(2129.22, raoResult.getFlow(crac.getInstant(InstantKind.PREVENTIVE), cnec, TwoSides.ONE, Unit.AMPERE), 1.); // why different from above?
         assertEquals(128.12, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
         assertEquals(370.78, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
 
@@ -749,22 +749,22 @@ void testThreeCurativeInstantsWithSecondCurativeHavingNoCnecAndNoRa() {
         assertEquals(2371.88, raoResult.getFlow(null, cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(2129.22, raoResult.getFlow(crac.getInstant(InstantKind.PREVENTIVE), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(1549.18, raoResult.getFlow(crac.getInstant("curative1"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
-        assertEquals(28.12, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
-        assertEquals(270.78, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
-        assertEquals(850.82, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
+        assertEquals(-271.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
+        assertEquals(-29.22, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
+        assertEquals(550.82, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
 
         cnec = crac.getFlowCnec("c1-cur3");
         assertEquals(2371.88, raoResult.getFlow(null, cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(2129.22, raoResult.getFlow(crac.getInstant(InstantKind.PREVENTIVE), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(1549.18, raoResult.getFlow(crac.getInstant("curative1"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(432.73, raoResult.getFlow(crac.getInstant("curative3"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
-        assertEquals(-671.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
-        assertEquals(-429.22, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
-        assertEquals(150.82, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
-        assertEquals(1267.27, raoResult.getMargin(crac.getInstant("curative3"), cnec, Unit.AMPERE), 1.);
+        assertEquals(-871.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
+        assertEquals(-629.22, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
+        assertEquals(-49.18, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
+        assertEquals(1067.27, raoResult.getMargin(crac.getInstant("curative3"), cnec, Unit.AMPERE), 1.);
 
-        assertEquals(671.88, raoResult.getFunctionalCost(null), 1.);
-        assertEquals(429.22, raoResult.getFunctionalCost(crac.getInstant(InstantKind.PREVENTIVE)), 1.);
+        assertEquals(871.88, raoResult.getFunctionalCost(null), 1.);
+        assertEquals(629.22, raoResult.getFunctionalCost(crac.getInstant(InstantKind.PREVENTIVE)), 1.);
         assertEquals(-20.30, raoResult.getFunctionalCost(crac.getInstant("curative1")), 1.);
         assertEquals(-20.30, raoResult.getFunctionalCost(crac.getInstant("curative3")), 1.);
     }
@@ -790,13 +790,13 @@ void testThreeCurativeInstants() {
             .newThreshold().withSide(TwoSides.ONE).withMax(2500.).withUnit(Unit.AMPERE).add()
             .withOptimized().add();
         crac.newFlowCnec().withId("c1-cur1").withInstant("curative1").withContingency("co1").withNetworkElement("FFR1AA1  FFR4AA1  1").withNominalVoltage(400.)
-            .newThreshold().withSide(TwoSides.ONE).withMax(2400.).withUnit(Unit.AMPERE).add()
+            .newThreshold().withSide(TwoSides.ONE).withMax(2100.).withUnit(Unit.AMPERE).add()
             .withOptimized().add();
         crac.newFlowCnec().withId("c1-cur2").withInstant("curative2").withContingency("co1").withNetworkElement("FFR1AA1  FFR4AA1  1").withNominalVoltage(400.)
-            .newThreshold().withSide(TwoSides.ONE).withMax(2300.).withUnit(Unit.AMPERE).add()
+            .newThreshold().withSide(TwoSides.ONE).withMax(1500.).withUnit(Unit.AMPERE).add()
             .withOptimized().add();
         crac.newFlowCnec().withId("c1-cur3").withInstant("curative3").withContingency("co1").withNetworkElement("FFR1AA1  FFR4AA1  1").withNominalVoltage(400.)
-            .newThreshold().withSide(TwoSides.ONE).withMax(1700.).withUnit(Unit.AMPERE).add()
+            .newThreshold().withSide(TwoSides.ONE).withMax(1000.).withUnit(Unit.AMPERE).add()
             .withOptimized().add();
 
         NetworkAction pstPrev = crac.newNetworkAction().withId("pst_fr@10-prev")
@@ -844,19 +844,19 @@ void testThreeCurativeInstants() {
         assertEquals(2371.88, raoResult.getFlow(null, cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(2129.22, raoResult.getFlow(crac.getInstant(InstantKind.PREVENTIVE), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(1549.18, raoResult.getFlow(crac.getInstant("curative1"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
-        assertEquals(28.12, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
-        assertEquals(270.78, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
-        assertEquals(850.82, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
+        assertEquals(-271.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
+        assertEquals(-29.22, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
+        assertEquals(550.82, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
 
         cnec = crac.getFlowCnec("c1-cur2");
         assertEquals(2371.88, raoResult.getFlow(null, cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(2129.22, raoResult.getFlow(crac.getInstant(InstantKind.PREVENTIVE), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(1549.18, raoResult.getFlow(crac.getInstant("curative1"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(990.32, raoResult.getFlow(crac.getInstant("curative2"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
-        assertEquals(-71.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
-        assertEquals(170.78, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
-        assertEquals(750.82, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
-        assertEquals(1309.68, raoResult.getMargin(crac.getInstant("curative2"), cnec, Unit.AMPERE), 1.);
+        assertEquals(-871.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
+        assertEquals(-629.22, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
+        assertEquals(-49.18, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
+        assertEquals(509.68, raoResult.getMargin(crac.getInstant("curative2"), cnec, Unit.AMPERE), 1.);
 
         cnec = crac.getFlowCnec("c1-cur3");
         assertEquals(2371.88, raoResult.getFlow(null, cnec, TwoSides.ONE, Unit.AMPERE), 1.);
@@ -864,14 +864,14 @@ void testThreeCurativeInstants() {
         assertEquals(1549.18, raoResult.getFlow(crac.getInstant("curative1"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(990.32, raoResult.getFlow(crac.getInstant("curative2"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
         assertEquals(432.73, raoResult.getFlow(crac.getInstant("curative3"), cnec, TwoSides.ONE, Unit.AMPERE), 1.);
-        assertEquals(-671.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
-        assertEquals(-429.22, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
-        assertEquals(150.82, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
-        assertEquals(709.68, raoResult.getMargin(crac.getInstant("curative2"), cnec, Unit.AMPERE), 1.);
-        assertEquals(1267.27, raoResult.getMargin(crac.getInstant("curative3"), cnec, Unit.AMPERE), 1.);
-
-        assertEquals(671.88, raoResult.getFunctionalCost(null), 1.);
-        assertEquals(429.22, raoResult.getFunctionalCost(crac.getInstant(InstantKind.PREVENTIVE)), 1.);
+        assertEquals(-1371.88, raoResult.getMargin(null, cnec, Unit.AMPERE), 1.);
+        assertEquals(-1129.22, raoResult.getMargin(crac.getInstant(InstantKind.PREVENTIVE), cnec, Unit.AMPERE), 1.);
+        assertEquals(-549.18, raoResult.getMargin(crac.getInstant("curative1"), cnec, Unit.AMPERE), 1.);
+        assertEquals(9.68, raoResult.getMargin(crac.getInstant("curative2"), cnec, Unit.AMPERE), 1.);
+        assertEquals(567.27, raoResult.getMargin(crac.getInstant("curative3"), cnec, Unit.AMPERE), 1.);
+
+        assertEquals(1371.88, raoResult.getFunctionalCost(null), 1.);
+        assertEquals(1129.22, raoResult.getFunctionalCost(crac.getInstant(InstantKind.PREVENTIVE)), 1.);
         assertEquals(-20.30, raoResult.getFunctionalCost(crac.getInstant("curative1")), 1.);
         assertEquals(-20.30, raoResult.getFunctionalCost(crac.getInstant("curative2")), 1.);
         assertEquals(-20.30, raoResult.getFunctionalCost(crac.getInstant("curative3")), 1.);
diff --git a/ra-optimisation/search-tree-rao/src/test/resources/crac/small-crac-ra-limits-per-instant-3-tsos.json b/ra-optimisation/search-tree-rao/src/test/resources/crac/small-crac-ra-limits-per-instant-3-tsos.json
index 4f3c638004..5fd8abc047 100644
--- a/ra-optimisation/search-tree-rao/src/test/resources/crac/small-crac-ra-limits-per-instant-3-tsos.json
+++ b/ra-optimisation/search-tree-rao/src/test/resources/crac/small-crac-ra-limits-per-instant-3-tsos.json
@@ -116,8 +116,8 @@
     "nominalV" : [ 400.0 ],
     "thresholds" : [ {
       "unit" : "ampere",
-      "min" : -1000.0,
-      "max" : 1000.0,
+      "min" : -1700.0,
+      "max" : 1700.0,
       "side" : "left"
     } ]
   }, {
@@ -133,8 +133,8 @@
     "nominalV" : [ 400.0 ],
     "thresholds" : [ {
       "unit" : "ampere",
-      "min" : -600.0,
-      "max" : 600.0,
+      "min" : -1000.0,
+      "max" : 1000.0,
       "side" : "left"
     } ]
   } ],