Haha, yeah, I experienced a similar scenario kernik. I think the amount of coins in a single output definitely matters. I am actively experimenting, now that I have a better understanding of staking from ranlo.
I will separate my larger PoS wallets into multiple addresses, each with single outputs as not to clog things up, like you mentioned kernik. Let's see what happens.....

clovis
every input splits in about half everytime it stakes. The recommended way is to have everything in one address in ~200 size chunks