does charging lipo's at low amp decrease punch?

[blueb8llz]

after the run, my 3s lipos reads 3.90 4.11 4.01
i would say thats pretty bad haha. so you think i would see a power/punch increase if i was to purchase the EXACT same zippy lipos or will i just see an increase in run time?
one other thing, why are my zippys so unbalanced in the first place? is it because theyre cheap batteries, cus if thats the case, wouldnt brand new ones do the same thing?
or is it because those lipos are getting old? i bought them used with the truck.