I'm not sure where you got the amp ratings but the Lume1 driver in the E12R is regulated to 6A and has FET for turbo. The E12C has a FET+12 driver with a max regulated level of 4.2A but it is much less efficient compared to the buck driver.
Another advantage for the E12R is the optic. It's a much better optic with a nice round throwy hotspot.
I actually own both of these lights and am currently trying to sell my E12C lol
Edit: I see now that you're talking about the power bank amp ratings ๐คฆโโ๏ธ