I have the Paraboard the EPBuddy sells and it is not limited like that. If the HK description is accurate (and I believe it is in error), they must have copied something about the wiring wrong, cause it is a copy. You're correct - you can charge same cell counts of different capacities in parallel. I routinely do it and you can find many vid clips on UTube of folks doing it. Dave Gray, owner of Progressive RC (iCharger Dealer) has one where he's charging 6 diff lipos all 3S, but all of diff capacities in parallel.

http://www.youtube.com/watch?v=NczQwVTI2bY

C Rate ideally should be the same, but there some prob here since there is no standard for setting the C rate and one companies 25C may be another companies 30C and yet anothers 20C. So even if the 'label' C ratings are the same, the actual C rates may not be. I try to match them.