I'm am absolutely sure you're incorrect regarding IR and cell size. A 20k pack will always have lower IR and than a 2k pack. All of my ULCG batteries average upper 1 to mid 2ir, the better ones are mid to low 1. My non-ulcg batteries averaged below 1 to 1.5ir.

I agree about voltage drop, that's why I mentioned voltage drop. During my battery cycles I record how long it stays above 4v during a 20 amp discharge on an icharger. The better packs stay above 4v around 1.5+ min.