Add Volumetric Weight to Shipping Cost Calculation

[sght500]

I’ve added a feature that calculates volumetric weight (length × width × height ÷ 5000) and compares it to the actual weight. The system now charges based on whichever is greater, following industry standards used by carriers. This ensures more accurate shipping costs, especially for bulkier packages. I believe this will improve cost accuracy and make the feature more reliable for users handling varied package sizes.

Please see the attached image with a snippet of the code change and a test of our new feature: