As I understand this deal, the vote is sort of a two part thing.
1. the creditors vote their exposure to the company, i.e. the money. for this to pass, the folks with the most money to lose have a bigger vote than those with less to lose. this is why U wants the big creditors onboard.
2. 1 man, 1 vote. all creditors vote to accept/reject the reorg plan, and at least half must approve for the plan to go forward.