In parallel, same cell counts, can be diff capacities....
http://www.rchelicopterfun.com/paral...-charging.html
See 6th paragraph - they can be diff capacities (within reason) - you wouldn't parallel charge 2200, 4000, 6000 and a 450mah 2S lipos together.
Most of what you see on the net as examples are the same capacities, but that's just because that's what they need or have to charge, not that it's required part of parallel charging.