An interesting solution to an annoying problem.
If it were me, I would instead use something like AutoIT, I believe it changed its name some time ago, to send a down key every second, but only when the MSFS window has focus.
AutoIT is a scripting language for automation, and it can export a binary that can be run. You could even add a hot key sequence to enable/disable the key presses when you don’t need it, like in the map screen for example.
It’s very easy to use, having a BASIC like syntax.
The last time I used AutoIT was with X-Plane, so I could more easily interact with ATC via the buttons on my yoke.