Thought I would post this here for future reference. I was concerned that my fans weren't coming on fully even though in KS I was setting them to 100% duty cycle. After some investigation I found that the M106 command was being inserted as follows: M106 SXXX when in fact it should be M106 PXXX. So, after manually editing the *.BFB file to change the S to P, my Cubex now controls the fan with the duty cycles set by the sliders in KS 1.5.
MJ