Dan, not a single other person has mentioned a similar situation to yours with Costco. Why do you feel the need to repost your savings, seemingly as a rebuttal to those maximizing their gas savings with the PenFed card? It'd be one thing if many people would benefit by emulating your gas strategy, but most of us are stuck with regular old expensive gas stations that take all types of cards.
On a separate note, someone mentioned (too lazy to go back and quote - sorry) buying gc's to use for gas in a supermarket when chase freedom had 5% on groceries. Would that work buying gc's from gas stations with the PenFed, to get the 5% without paying the cc fee? and if so, anyone know which stations generally sell gc's in the NY area?
Also, what happens with debit cards (which is essentially what gift cards are). If you pay at the pump with a debit card does it charge you the cash price of the cc price?