Don’t forget you need to remap both “SupplyCrate_level” and “SupplyCrate_level_double” - the latter can have more and higher quality loot, but the items are the same.
Also, if you’re doing this as a normal mod, you need to copy the PrimalGameData to your mod folder and rename it to PrimalGameData_something-something before cooking.
Any files/changes within the default folders will be ignored unless you cook a total conversion mod.