You are correct.....pobably, lol.
Almost all of the time, they either work, or don't! If you have spark, that is not the problem.
However.......I have come across 2 in the last 20 years....one on a briggs, one on a Tec....that after chasing everything I changed the mag and fixed the problem. The nags I had tested and they said they had an internal short...Like I said that was 2, in 20 years!
I don't know if anyone has said this yet...did you check the flywheel to see if you possibly sheered the key? If the Flywheel has moved, it will be out of time.