Internal time code as stopwatch

I have simple start and stop macros for time code to use as a magic sheet stopwatch. Two things I noticed while setting this up:

1. Each time the internal the code starts and stops the * shows up on the show file name at the top indicating unsaved changes. What is the reason for that?

2. When the internal time code is running with the red numbers on the top left of the screen the show file name jitters as the frames and second change. Could the font be changed to a mono space version to avoid this?