The thing I notice quite a bit when I rarely run a tank of 87 (usually when I purge my 30 gallons of summer time hurricane gas) is the transmission does a lot of gear hunting and seems more confused. I imagine it’s because it upshifts too quickly and there isn’t enough power, so it bogs down and down shifts again. My father in law and friends with the standard eco boost note the same behavior and now only run 93.