Background: USPS changed their rates last month to use dimensional weight. Since USPS uses commerical airlines to ship Priority Mail, they are not charged by weight, but by volume. Most Priority Mail is under 1 cubic foot and USPS preprinted boxes and Flat Rate boxes are all under 1 cubic foot. Any Priority Mail box over 1 cubic foot not being mailed locally (ground) will be surcharged and CSC will not get accurate rates from the real time shipping module (shipping will be under charged.)
CSC should be enhanced to capture the item’s dimensions. (The fields are already in the database.) Using a best fit total size algorithm, items totaling 1 cubic foot or less are not surcharged by USPS Priority mail. Over 1 cubic foot, size parameters in the XML need to be sent to USPS for accurate rate quotes. If you add a new table to hold box sizes and box weight used, the “view orders” could tell us which box to pack the items into. (By the way, UPS and FedEx both use dimensional weight. If you ship lightweight items in large boxes, you know all too well about surcharging.)
I can’t provide a solution, but I agree that there needs to be a way to define the dimensions per product. If this mod gets written, I would be happy to chip in.