The Ultragauge STILL reads mileage when the engine is off and it's saying error. This was a constant thing I saw when I was EOCing with my Auto RAV4. Before I realized that was NOT a good thing to do. One way to prove it really quick is to take note of the mileage before you kill the engine, then see what it shows when you bump start.
It will be higher.
Your kill switch looks great!
Way to go!
What vehicle is that? And what are you killing? Are there any more details you want to add that will help other people driving a manual of your type of car?