My 2014 F150 with 3.5 EB engine will top 100k miles when the oil is changed next time. It's at 96k miles now and the oil is changed every 5k miles. Until now, I've always used Motorcraft 5w-30 Synthetic Blend oil. Would it make any sense to change to a high mileage full synthetic oil next time, or just continue using the current Motorcraft syn blend?