The discount is miniscule. What, a penny per gallon? So if I rolled in there on fumes, I could save a whole, whopping $1.65 on a fill-up? Be still, my beating heart!
No -- the discount he's talking about is the "cash" discount, which now ranges from $0.07 to $0.09 per gallon. Flying-J USED to give RV'ers the cash discount at the truck pumps, even when paying with a credit card, so long as you presented your (free) frequent fueler card.
So you're looking now at a surcharge, in the case of your tank, of about $16 to fill up using a credit card. In my case, it's over $30.
We used to use the truck islands at FJ exclusively, because it takes anywhere from two to five times as long to fuel at the RV island, and even longer at a car dispenser. When you have a 300+ gallon tank, that can be the difference between a 15-minute fuel stop and an hour and a half.
FJ still honors the cash discount at the RV islands, and now we fuel there instead. We just budget an hour or so to fuel -- and we warn off anyone pulling up behind us.