I’ve been at facilities where the entire amount is selected at the end of the bidding. I’ve been at facilities where if everyone says they are done during the bidding period, and based on process spelled out in the mou, the remaining days can be selected however they want. Any remaining slots remain open until 30 days prior to the posting of the schedule. At which point request for leave can be denied if management follows the normal denial process.
You are correct however Your mou can specifically allow this and have to say people can bid excess leave but only after every employee has said they chance and are done bidding, slots remain, and people won’t be allowed to select more slots than was available at the beginning of the bid process