It's an odd power, but awesome! I didn't have it on the posted build because it pre-dates the changes to FF.
Dampening Bubble is a combination of resistance to debuffs for your team and weakened debuffs for your enemies. So it's not that the enemies have their tohit dropped by 43% but rather, their ability to debuff you and your team is reduced by 43% and an additional 43% resistance to tohit debuff if the team member is inside the bubble! Same thing for debuffs to Defense, regen, perception, and slows.
https://cod.uberguy.net/html/power.html?power=defender_buff.force_field.force_bubble&at=defender (look at both redirects one is for team, the other for enemies, the third is for the bubble's "look".)