Just so people know how 12's energy absorption works: If and when an android absorbs someones power, not all of it is permanent. He gains a permanent power boost which varies depending on the energy drained and who it was drained from, and some extra energy that is expendable. Also, he will probably try to take as much as he can from enemies, especially when they no longer pose a threat and he doesn't have to worry about them getting away. So basically, he acts like a vulture in that regard.