I’m kind of surprised to see people running 91 octane in this car... You’re just wasting money unless the car is designed for higher octane, and there’s no evidence that the Ascent is.
For you folks who actually asked Subaru about the 85 octane fuel available in your area, did you specify in your question that you are operating at high altitude?
most modern cars have sensors to compensate for altitudeAir is less dense at altitude. Air and fuel is what is mixed in the engine to make it go. The theory is, that, if the air is less dense then the fuel needed can have less of an octane rating