maybe one port 2.1A while another 0.9A?

Then again can note charge at 3A...doesnt it have a internal circuit that limits the charge at 2A?
Note II internal circuit board should theoretically take in a maximum of 2A 5V(but will unlikely hit the cap due to power loss)
it is protected by fuse and other circuitries protection to cap a limit. give 3A will also take in 2A.
If the phone takes in whatever the output by the charger is, sure kaboom if somebody can find a 5A-10A mobile phone charger
As for the innergie charger, must rely on expert to ripped out the internals to verify. As far as I know those china dual output charger etc, they are shared.
For the yoobao 11200mah, the 1A and 2A ports operate independently making it the juiciest portable charger.