Is there a canonical definition of "consumed"? I didn't think United used that term. I think United's rules for the use of PP makes this an angels-on-the-head-of-a-pin question. Since you cannot apply PP to a flight whose date is after the PPs expire, there is no way to tell the difference between a world in which they are consumed at deduction, and one where they're consumed at departure. If you fly the upgraded flight, the PPs are gone forever, either way. If you cancel the flight/upgrade, then in one world you get "your" PP back, and in the other you get refunded "new" PP with the same expiration date as the ones that got consumed.