Strange Mechanics: Success And Effect In One Roll

    An idea, since things seem to be popping in my head to distract me from the project I'm working on.  I like zero-based dynamics, that is, games like Fate where the dice tend towards zero, and thus your character's base skill/competence, and go a little plus or minus.  The flat d20 roll and ever-inflating bonuses just feels out of balance to me.  So I had this idea and thought I'd share it.
    Take 2 ten-sided dice, each of a different color.  I'll use Green and Red for this illustration.  You have a skill, could even just be your level.  Roll the dice and add to your skill Green minus Red.  So it will be a -9 to +9 bonus, that should tend towards 0.  From your total, subtract a modifier for difficulty, say Easy 0, Hard -5, Incredible -10.  You skill/base + roll - difficulty then makes a total.  To determine your success, look at the following table:

1 or less    Botch - you made things worse
2 - 5          Fail - you did not accomplish what you wanted
6 - 11        Partial - you sort of succeeded, but not completely
12 - 15      Success - you did what you wanted
16+           Extra - you got more than you wanted

    Now, if you roll a Botch or Fail, take the highest of your two dice and lose that many points.  So, taking combat as an example, lose that many HP.  If you get a Success or Extra, take your highest die and inflict that many points on your opponent.  If you get a Partial, if that die is odd go up to the next even number, then split the results between your cost and your effect on the opponent.  If you get a Botch or Extra, the GM will describe how the situation gets worse or better.
    Weapons could give a bonus to the effect number, and armor could lessen the cost number.  Everything could get a form of HP, like you need so many points to influence a merchant vs so many for a guard.  Maybe a good reputation could be "armor" or even a "weapon" adding to effect totals or reducing cost totals.

    I've had in my head a desire to make as much of a one-roll system as possible.  I'd like to keep modifiers low and the number of things to add/manipulate as few as possible.  I'm not fond of this system because subtracting is more work than adding, granted not by a lot but still.  I do kind of like it more than the "roll over target number" and even the "every point over is a point of effect."  Just going over a number does not feel to me like a good measure of success, just effect, and while the two are related they kind of aren't as well.  I don't know, now I'm babbling on paper (so to speak) - this is an odd idea, not sure if it's worth using or if I ever would try to use it, but there it is.