Honest question why change fuels in the winter? Assuming it's cuz traction in the snow limits you? I've always ran 93 winter and summer as I'm in Houston Texas so no snow.
Why only use it when it's over 85? Can't you use the power as long as there is traction? Is there a cooling affect to higher octanes?
In the summer, the 94 just gives a
slightly better hedge against knock/detonation, possibly even LSPI(?), yes even
within the Ford OAR, and knock sensor parameters.
I don't necessarily use it to gain the not even infinitesimal power increase it
might yield.
Traction is limited in the winter not just from the cold ambient temps, (and the tiny bit more power anyway due to colder charge air temps via the intercooler), but also because I use narrower winter/snow tires and wheels, which are not made for ultimate accelerative, nor lateral traction.