I would assume this wouldn't be possible if doing rules as written but I will allow you to expend all of one of the two abilities, not both.
Works for me.
However, I'm also not going to throw empty skill checks at you to use it up.
Like, I'm not looking for empty skill checks, I'm looking at a situation we're going into and thinking "that would be a place I'd expect skill checks to be and I have powers that can help with that" and then "maybe the GM will let me do something neat to help us through it". You know, RPG-ing.
Trying to use skill check powers reactively in a play-by-post situation is kind of a pain in the ass, especially with my work schedule. By the time I usually get to respond to someone's skill check, they've already replied and the opportunity is passed. So, laying out some preemptive bonuses to be used at the next requirement seems a good compromise. If it seemed like a big ask, well, it was. Never hurts to shoot for the moon, y'know?