Shipping rates are always adding a mysterious $1.00. I have only one shipping rate which is "per item" and I've set the per item charge at $2.50 and the handling at $7.50. That should equal $10 for 1 item, but it always shows (upon shipping calculation) as $11.00. If I change the figures in anyway say "per item" to $2.00 - the calculated rate then goes to say $10.45.... and it doesn't make sense. What is affecting this rate other than the settings under Modules/Shipping??