If you want to spend fate to make a test open-ended it looks like you have to make this decision  before  you roll, when the rules let you decide after you roll. I suppose the options are (a) do that, but then don't subtract the fate point unless it was necessary, which means looking at the die results and doing some inferring, or (b) never use the feature and roll more dice manually if you get a 6, repeating as necessary. Or am I missing something? Btw, I'll still love this character sheet even if there isn't an elegant solution to the above question.  Hats off to the creator! --Peter