I remember seeing a local article on this last week but can't find it. Though not local, the story is the same.
http://ap.lancasteronline.com/4/pa_gas_prices_pa_
This is true at Merrymeeting. The pumps are set at 1/2 gallon prices and you need to double the amount to get the acutal total. There is a notice on the pump but none of the usual signage on above.