I am a NW Plat and flew a complicated ITN this past week. Flew GRR-MSP on NW metal and was upgraded with my NW FF#, then flew MSP-SLC on Detal metal with a NW Co-Share flight number. Boarding Pass showed my NW FF#. Then about 9 hours later I caught a flight SLC-SEA on Delta with an Alaskan flight number. However, the Boarding pass had a Delta FF#. I asked the gate agent to change the number, but was told since I have already flew two segments they couldn't change it. Furthermore, my MSP-SLC flight also had the Deltal number attached! I showed him the boarding pass for the MSP-SLC with the NW FF# and said that is wierd, but he can't change the number.

so then I check-in for my flight SEA-DTW, and it also shows a Delta FF#. I was able to change the number back to NW and I still had my upgrade.

Has anyone else ever had this happen? Were you able to get credit on NW for these flights?