new USPS plug in is charging a higher shipping rate than the actual rate

Hey I installed the new USPS plug in for my page www.floridasdying.com/catalog and I have noticed it is charging higher postage rates for overseas packages than it should be. An order that zencart acknowledges is just under 8 oz is charging over $17 for postage while the actual postage is closer to $12. These price hikes make business hard enough but these inflated prices are going to scare away the remaining overseas business I have. I reduced my handling charge to .50 when the new rates kicked in so I know that is not the problem. Is anyone else having similar problems? Does anyone know how to fix this problem

I just added COP CITY/ CHILL PILLARS - "Held Hostage on Planet Chill" LP Item weight 0.5625 pounds

to the cart and asked for an estimate to Australia.

Shipping Estimator shows: 1.12 pounds so I assume that you have a tare weight of a bit over half pound being added for packaging.
Shipping Estimator quotes: $18.95 FirstClass

USPS.com quotes $18.60 for a 1.12 pound package

Discounted postage from Endicia quotes: $16.74 for the package weighing 1.12 pounds

And Ajeh will know much more than I

What is your Ship To?

What is your Ship From?

What are the settings in Configuration ... Shipping/Packaging ...

What rates are you getting in your shop?

What rates are you getting on USPS.com?