What's needed is a "package manger" on the admin side and then shipping adjustments to fully support combining products into packages as well as supporting dimensional weights for all packages. This has been discussed at length in other threads.
The package manger would manage the sizes/weights and dimensions of available packing materials. It would look at dimensions of a product and then figure out the best package to use based on weight/cost of the items. Exceptions need to be handled like must ship alone, combine only with with other designated products, insulated packaging, haz-mat/bio-mat packaging, etc.
Apparently 3rd party devs don't want to touch this.?
I already calculate dimensional weight (basically what dvsgr's addon does) and use it as the weight with no dimensions defined. This works close enough for me. The issue I have is once the weight reaches 150, then you get either no shipping method available or it gets thrown into a freight method if you have one defined.
Does anyone know what exactly the Max box weight actually does? You would think it would create another shipment if that limit was reached but not in my case.
I believe the max box weight is the limit of a "package". Hence if I buy 4, 50lb widgets, I will end up with 2 boxes. one at 150 and the other at 50. But this is dependent on the packaging setup for the product. Originally (before "packaging" in cs-cart) it was the total weight of a shipment.
The issue why (my opinion) most developers don't like to address shipping issues is that cs-cart bases its shipping on products rather than on packaging. I can say that 3 of these will go in a box but it doesn't tell me which box, nor whether that box has any room for other products. It assumes that each product will be in its own package.
Cs-cart shipping has been its weak point since day one. It's been incrementally improved but what's needed is a full overhaul. However, there's a lot of risk to their business in doing so given the number of people who will be pissed off to have to redo all their shipping specs so that it can be done correctly. Especially those where the current scheme is working for them.