The main factor is the type of BEC that is built in to the Align ESC. IANAE on ESC's, but to my knowledge, the built-in BEC is a linear type, rather than a switching type like the BEC's that come in better ESC's and separate BEC's like the ParkBEC / SportBEC. Raising the voltage (by using a 4S pack) will result in a lot of heat build-up in the ESC, which is bad. The other issue is the limited total current (2A) that the BEC is capable of supplying, which may not be a factor for you if you're not using digital cyclic servos.

It may well work for you, but I'd hate to see you fry your ESC. I'm just passing along advice that was given to me when I experimented with 4S. Take it for what it's worth.