Are you getting orders where customers choose shipping methods which is not applicable to their shipping zones? Like customers in Hawaii choosing UPS Ground instead of say.., Air Method? We now have a Yahoo Store Shipping Method Blocker which blocks shipping method based on country or state.
This special module will remove the shipping methods which are not relevant to any shipping address. For example Hawaii customers will not be able to choose UPS Ground. Or International customers can not choose US ground to avoid the higher priced International Shipping method and then getting away with that in the smaller final order total.
If a customer enters APO or PO Box address, it can be made to show only the available USPS methods since, as we all know, UPS does not ship to PO boxes or APO.