Thanks Steve for your prompt response!
I got 70% with car both off, and running/revving. There was no fluctuation at all. The Bosch readout may have been a different %, I don't recall, but nonetheless was a constant reading with engine running.
I see your circuit 50 on the schematic and it relates to the plug connection on the starter lockout switch. This is on the X26, 12 pin plug connection of the engine wiring harness.
How do I go about testing this circuit for voltage? Is there a fuse for this circuit 50 that I can check?