Fluctuating Shipping Prices via USPS 2-3 Day priority for a FLAT Rate Box

[ls1rx7]

For some reason when I print out a shipping label via USPS 2-3 Day priority (using a FLAT RATE BOX), the price keeps fluctuating. It's supposed to be a flat rate $4.85 regardless of destination/weight, but sometimes it says $4.95, $5.15, $5.05, and even $5.40. What gives? I've been shipping the same item since 2006 and it weighs only 12 ounces using the small USPS Priority DVD box with dimensions: 8-5/8" x 5-3/8" x 1-5/8". I used to pay like $3.50 back in 2006. Shipping is so expensive now, I can barely make a profit especially with the Ebay Fees + PayPal Fees.

[Tulkos]

I've been having the same issue, I've had to go to USPS.com a couple times in order to ship a package just because sometimes Paypals shipping charge cost half a dollar more for apparently no reason at all. Then again sometimes it's the same as the USPS. This started right after the USPS people changed the price, it must have messed with paypals system some how.