FitM with FitE Ygg style ponderings

In both the combat system and and the skill system I'm having something which is both FitM and FitE.

Basically you can either state intention and see if you succeed or state general intention and do specialized stuff if you roll high enough.

Or to take an example:

Let's say I want to make a painting.

I can declare before making the roll that I want to make it in half the time. I then roll to determine if I succeed or not.

OR I can just make a roll and then if the roll is high enough I can declare that it was made in half the time.

I make the distinction because that's how things work "in real life". Sometimes it just happened better than expected and sometimes you tried to do it better than usual just to begin with.

Anyway, to get to the heart of the matter.

Originally I was thinking that the currency would work like this: If I state 1 point of advantage BEFORE making the roll, that reduces my chance of succeeding by 1. If I fail the roll, I need to make two points of concessions for every point I failed the roll by.

If I make it afterwards, then I need 2 points of extra success for every point of advantage.

Maybe that wasn't quite clear. What I mean is that paying for advantages is cheaper if it's done before the roll is made, however the chance of success is lower, even though you can default to a "normal success" if you tried an advantage move you pay more for it. However, doing a general move and using a good enough result to gain extra advantages to do the same thing is too costly.

In the painting example, it's easier to succeed if you do it without trying to hurry, but your chances of doing it in half the time is less than if you stated you wanted to do it in half the time to begin with.

It's reasonable behaviour but...

What I'm thinking about is... Is it fun? Apart from the overhead with the currency issue, it's also dealing with the situations differently which requires some extra thinking. Do I really lose a lot by making them identical? So that if I state my intention before or after rolling makes no difference whatsoever. That way if I don't roll high enough I can default to some other action despite my original declaration without any punishment. It will be easier to optimize moves this way, but it seems simpler and more fun.

Any opinion on it? Is it clear what I mean?