First of all: there's a thread on the 406 Duo.
The 406 Duo can even charge two 6S Lipos at 40A each at the same time, so 12A is no problem (capacity is not a factor in this) - question is, if your power supply has enough juice for either...
Discharge is limited to 10A per channel without external resistors, IIRC.
Storage just uses charge or discharge settings as above, and stops at the set storage voltage, so no different limits apply.