Magento – Get cart items from shipping carrier

It's almost certainly a bug, since Magento is not sorting the condition values in any way. Rates are not sorted during import either (as you can see, entries are inserted in the same order they are found in the CSV using insertArray), so Magento is still able to load the correct rate if the order in the import is correct. This query you submitted can lead to wrong results though, without one noticing.

To fix this, it would be enough to edit Mage_Shipping_Model_Resource_Carrier_Tablerate, line 128 (CE 1.7.0.2) with:

->order(array('dest_country_id DESC', 'dest_region_id DESC', 'dest_zip DESC', 'condition_value DESC'))

A pull request would be the right thing to do I guess.

I wrote the WSA Dimensional Shipping extension, and its something that has taken me nearly 4 years on/off working on it for days on end to get it so that its useful.

As discussed you can just put in the dimensions to Fedex but this only works if you have all your products shipping in their own box or of you box everything in the 1 same box.

You do anything more than that you are in need of complex algorithms to manage it. We are still working on Dimensional Shipping and constantly improving it and adding in new features. It's not a magic bullet as bin packing is a np-hard issue. But I know thro experience we can get the rates much more accurate than anything else out there. There is always an investment of effort.

Sometimes tho writing your own on this can be worthwhile, you would need to get the FedEx API and then write an algorithm that meets your needs to do the bin packing. As our extension is sold to many people we have features in there that you may not need so writing yourself can be useful. Just bear in mind it could take a while, and you would definitely need TDD if you are doing anything but very simple calculations.