Assigning a package to a specific product?

[Blayr]

This doesn’t help when Shopify uses that package to calculate rates. For instance, our box holds roughly 25 lbs. of product, but our customers can add 75 lbs of product at checkout and only get charged for one box that holds 25lbs. So we have to foot the bill for 2 extra boxes and extra shipping for that extra 50lbs. Shopify offers different packages in settings, why can’t they have a SIMPLE function, if over X weight or X size, use THIS box instead or add an additional package.