@khan.orak
I've disabled that on all situations, so I can safely say that's not the reason. Thanks anyway!

@Eztran
The issue is, from what I've seen, the issue is in the idle state, since my "device idle usage" went from 0% to 1% according to Battery Usage (which, apparently, is a big deal). And TOP command doesn't show what's happening when idle, only when the screen is on. I agree that 12mA isn't a lot, but i was used to 5mA with many background apps running, so I can say i'm spoiled!
By the way, i get 12mA even without a SIM inserted, so (unfortunately) i think it has nothing to do with signal strength