Movement Add and Subtract

[SpydirShellX]

Is it legal to add a subtract movement powers simultaneously?
Ex.
The Superheroic Speedster is running at some speed?
Supervillian Sloth drains Speedster's Running, but at the same time has a Running, UbO attack with lower running than speedster was using, but lots of NCM.
Would Speedster suddenly be moving at NCM?

Or if you did a similar thing, only instead of the Running UbO, you did Aid (Can add adders).

[Steve Long]

There's no rule that would prevent an attack that had two "contradictory" effects, though it strikes me as a probably bizarre, if not ridiculous, sort of thing to do. ;)