.it: Not reading Zxx commands + some sample loopings don't work correctly

[Aquellex]

When playing the modules in a player or OpenMPT (latest version), they sound fine, but with the plugin, Z commands don't seem to work, and some samples cut off abrasively instead of loop (see Executive Pay II in channels 3, 4, 7 & 8).
modules in question.zip

[mstop4]

I did some sanity tests by playing SE_OmniSpirit MAX!.it just using the FMOD API by itself (without any GMS integration):

In both versions 1.10.07 (the one included with FMODGMS) and 1.10.10 (the latest one) of FMOD, I can confirm that Zxx commands are being ignored. I highly suspect that this is a limitation of FMOD's module playback engine, since I also tried playing the module with the BASS audio library (which has a more accurate module playback engine) and the Zxx commands worked.

As for SE_Executive Pay II.it, I couldn't hear any samples abrasively cutting off in any of my tests, so I'm not sure what's causing that. I'll try again later to see if I can find that problem.