Apparently ethanol fuels start to sour at about 21-30 days according to tests by marine outfitters.
Phase separation (small amounts of water) in these fuels can really make engines run like crap, injectors problems & who knows what else.
I guess a good idea is to get your tank close to empty, and refill every couple of weeks.
I don't think water absorption in the fuel is that much of a problem in summer, but come winter time, if I was running ethanol fuels, an ethanol fuel stabilizer would get added frequently.
I recently came across a product that treats ethanol fuel well.
Starbrite Star Tron may be worth a try, & see if the PA runs any better Randall with it in the fuel.