Just changed the oil in my '07 Focus. The current OCI was 5,000 miles (35,000 miles on vehicle), and I decided to keep the Mobil 1 filter on for another 5,000 mile OCI. Out came the 0w-20 AFE & MoS2 blend, but about 0.5 quarts remained in the filter/oil galleys, and I added:
3 qts. Service Pro synthetic blend 5w-20 (SM)
1 qt. Havoline conventional 5w-20 (SN)