Try these weights in your USPS settings

Small FlatRate 0 - 5 pounds
Med FlatRate 0 - 19 pounds
LG FlatRate 0- 30 pounds

and see if it helps.

If someone purchases a wallet and/or perfumes, the SmFR should be removed from the choices
If someone purchase a 1 messenger bags, the small should be removed from choices.
If someone purchases 2 messenger bags, the small and med should be removed from the choices.
If someone purchases wedge, small and med should be removed from choices.

You are using logic similar to what we have been using for volume filtering. We can get 5 widgets into a SmFR, 7 widgets into a LG video and 9 or more widgets into a Med FR, so our volume for the widgets was 13 cubic inches which is set into digits 6-11 of the weight field.

Attachment 12836