I recently took my FGT to a local Ford dealer to have the axle bolt upgrade performed. I had the dealer do an engine oil and filter change service at the same time. Last night I happened to read the repair order and to my dismay I see that the dealer used Mobil 1 15W50! Should I be concerned? BTW, I specifically requested that the service adviser be sure that the tech use the recommended Motorcraft # XO-5W50-QGT oil!