no u gotta start the wprime calc FIRST then run the tweak. this is because wprime open 8 instances of the program only after it begins calc. If you apply the tweak before, it doesnt affect any of the new threads wprime starts.
Its a shame this was released public, I was working on exactly the same thing to public release under the PURE moniker :( Well at least I dont have to spend anymore time on the wprime tweaker. Though this program is much more full featured than mine was (I was only doing wprime tweaks since waza/screenshot/pifast etc all have other publically available tools to tweak them).
I still have something going they dont have in there though...