OK, with about 4 attempts with restoring from backup to erase my mistakes each time, I found the solution. 

First, it will not work with a 'service item', no matter how I set the three accounts in the item that is added to the assembly.

A Non-Inventory Item does work, but the 'Asset' account must be set to the account you want to use for the 'commission' or 'fee'  screengrab attached.