Newbie question: Flying J pump menu

Keep your eyes open on the pricing. If using a credit card the truck lanes have 2 prices and CC is usually 6 cents/gal higher. The RV/Auto lanes are the same price. I noticed at one Quik-Trip I stopped at the truck lanes and rv lanes were divided by the scales. The gas pumps were on the other side of the station. The rv lanes were 16 cents/gal cheaper?????

I don't have a clue how the Flying J card works AFA discount at the truck pumps, don't have one.