shipped the exact same chips in the same envelopes 3 days in a row and was charged a different price each time. When I questioned it to a supervisor, I was told "it's a gray area and subject the the interpetation of the postal employee". I told him that I seriously doubted that the pricing was discretionary and just kept going to the person that charged me the lower rate and I never drop the envelopes in the box without going to the window.