The voltages seem ok. GE doesn’t tell us much about the internals.
I believe the precharge could come from p17 through the coil from B+.
I do know that the controller “senses” p17, and will not go into program mode until disconnected.
This might help. I have not seen it.
For what it’s worth. I don’t know what armature offset voltage means. I can guess that its a voltage reading from the shunt. No load must have a specific range of voltages to verify shunt is working and motor is ok, before allowing car to run.