The K2 bed flexes quite a lot between ambient (cold) and heat soaked at the desired printing temperature. So, it is best to take a bed mesh at your desired printing temperature. However, the K2 also has both a large bed and a slow probe. As a result taking a detailed bed mesh at your desired printing temperature can add a non trivial amount of time to your print, each time.
But doesn't the K2 already take a bed mesh?
Yes, but during calibration it creates a bed mesh, but this is done at ambient temps. I highly doubt anyone is printing at ambient temperatures. Additionaly, it only stores a single "default" bed mesh.