I am, but not adding bonuses.
Over=positive outcome/yes
Under=negative outcome/no
1=Extreme negative/no, reset to 10.
20=Extreme positive/yes, reset to 10.
Equal=Reset to 10, envision two possible outcomes, and re-roll. Outcome 1=under Outcome 2=Over. 1=Outcome 1 with added threat 20=Outcome 2 with added advantage. Equal again is a reset to 10 and re-roll.