I recently ordered laptop memory from a MAJOR online retailer that was delivered in a half cubic foot box. [Pause while you picture this. Hint: picture a marble getting delivered inside a shoe box.]
This is a clear indication that many shipping operations have failed to adjust to the recent but significant changes in volume-based pricing. Apparently, it seems, many shippers do not realize that size does matter.
A half cubic foot box (6" x 12" x 12") which weighs up to 1 lb gets billed at a 5 lb rate. Sent by UPS Next Day Air® to zone 6, the 2008 list rate would have been $48.25. The 1 lb rate would have been only $32.55. Appropriate- sized packaging would have yielded a savings of $15.70.
You should make every effort to avoid getting "dinged" after the fact for dimensional weight charges that you did not and cannot pass along to your customers. If customers prepay for (estimated) freight charges, you should be sure to understand which products result in dim weight charges. Be sure to factor in this incremental amount or do what you can to reduce the dim weight charges through better packaging.
Building real-time rate shopping into your Order Entry process (taking both weight and dimensions into consideration) can eliminate this issue automatically. However, this requires that you store this data for your products, do not perform a lot of re-packing, and that you have the ability to integrate a rating engine into your Order Entry system and/or Shopping Cart.
Many shippers under estimate how significantly these charges can snowball and how easily a once-profit-generating shipping operation (or at least breakeven) can turn into a losing proposition.
Many third-party shipping systems can be configured to automatically prompt users for dimensions for express and/or ground shipments. They can also prompt the user to enter just a box code and then automatically recall dimensions for commonly used boxes. If your product dimensions are ever known, these dimensions can be imported too. Then, in all cases, dimensions can be incorporated into the rate.