The two should've worked fine at 10C or so (if they are really 15 C batts) It may not be the p set-up at fault.

I think that it went bad for another reason. Or to state it another way, a 5000-6000 pack would've also went bad. One thing is for sure though is that if 1 cell in 1 pack went bad, low V or whatever it can cause trouble with the other pack and cells.

It is strange that no one cell went down too low during use , yet after bech testing them they apparently did not fair well. On your savage esc, how were they hooked? and how was your montor hooked? I'm curious also as to the discharge rate or runtime you got with the sav. (flux or regular e-sav?)