1300C Maintenance Manual is wrong.
I have a 1300C and purchased the maintenance manual from HONDA. The instructions in the maintenance manual indicate that the oil should be check on the side stand. This does not match the owners manual so I called HONDA. They confirmed that the maintenance manual was wrong and the oil should be check with the bike level as you indicated. I tested and found that this makes a FULL QUART difference in the two methods of checking.
1300Doug