Power Store does not support different size boxes.
it would require making a number of modifications to the code.
you would need to add the width height length form elements to the product insert and update page and to the products table
you would need to edit the insert and update record behaviors on the products insert and update page to bind the new form elements to the new database columns.
You would need to edit the ecart object using eCart to create new columns for the hieght width and length.
you would need to edit the add to cart buttons to bind the new cart columns to the columns from the product recordset.
and finally edit the webassist/plugins/shopping_cart/calculate_shipping.php page to use the new cart columns for the height width and length.
all of these are not modifications that we can offer support for.
