I'm grasping at straws, but in studying the situation in seems to me the whole problem centers on a failure to clear the ram memory. Either due to error in procedure, wrong clear card or a corrupt clear card.
When you go through the clear procedure, what clear message do you get on the screen.
Attached is what I get on my machine.
UPDATE:
Attached are a couple of pages from the Field Setup Guide "FG-OS370B", the manual for your specific operating system 370B. If you would like me to send you a copy of the entire manual, private message me with your personal email. The file is too large to post here. According to the compatibility table, you have the correct Clear card, though I wonder if it is corrupt. In the device setup, when an incorrect device is selected, it will result in a COMM error. If the selection is locked and cannot be changed, you must do a ram clear in order to correct it. As you have shown, when you do a Clear and go to device setup, the incorrect printer is already selected and is locked. This tells me the Ram Clear failed.