ORIGINAL: c/f
I routinely charge my 3s 1320 for a eheli @ 1.5amps on a MCDuo V8.06 and never feel any heat at all with pack. Very disturbing and puzzling, I've been thinking of outfitting all my RC models with Lipo's as I have been very pleased with their predictable charge discharge cycles.
Unlike Ni-Cd batteries, Li-Poly batteries generate no heat when charging unless they catch fire. IMO you're just getting lucky. There is a reason manufacturers say to charge these at NO MORE than 1C.