So I noticed that EPtW has no effect on weapon drain if your at 125 weapon power level unbuffed, but EPS Power Transfer which is basically the same thing (the half that is to all power settings) does. So EPtW will only add to power that is below 125, but EPS-PT has no such limitation. So in my case there is no point in say... taking EPtW3 unless my weapon power is nearly 40 points below 125. All it can do at the cap is remove targeted subsystem drain, in which case there would be zero difference between the 3 different versions.
I'm not sure if this is intended or not, so I bugged it in-game & here on the boards.
If it is intended, then there needs to be some bonus to using this power at the cap like the others do.
EPtS heals your shields and gives resistance
EPtE gives you a speed buff
EPtA used to heal? Dev post here mentioned it receiving some other benefit.
EDIT: After more experimenting, all EPtW abilities have a cap of 135 to maximum power. It was hard to notice considering my default power was 131. Like I said above if this is intentional, it would be nice for it to have a secondary effect like the others.