I'm having problems exchanging the FSDs in some old ships to SCO. In most ships it has been no problem. But specifically with the old Python and the Chieftain it always says "incompatible slot". I'm trying to install 5A SCOs, as it should be correct. I also tried swapping the old FSD to a default 5E first and then install the SCO, but that doesn't solve the problem. What am I missing?