Wouldn't Bootstrap know who Barbossa was anyway? He was part of the crew during the mutiny.
I think Bootstrap mentions this, but here is how I understand it. Being part of the crew on the Dutchman, it doesn't just claim your body and soul, it claims your mind. You lose bits and pieces of who you are, and as that happens you become a slave of the ship...until you become a part of the ship.
I suspect that the bargain is rigged so that even if you manage to serve 100 years, your soul does not move on or find peace. I think that once you swear an oath to the Dutchman, you are trapped forever on that ship.