The worst case is that you get booked in Y, which gives the same EQMs as P. The gap would be that P earns 150% RDMs while Y gives just 125%. Of course, if this happens just call and get them to fix it manually.

I am curious about the outcome, however. I travel this week on a D fare and will probably SDC to a slightly better domestic flight to link up with the TATL leg. The flight I want to SDC to is down to F=1, so I am fully expecting to fly in Y on that short hop.