Hi Erik
There has been a bug in your firmware from the very beginning which can be a problem.
After setting up some presets and recalling them, I then try and set a new start frequency but it doesn't allow me too, it always sets it to 350MHz (when on high input mode), even worse if I then try and change the stop frequency.
The only way to overcome it and set a desired scan range is to power cycle the unit, select either low or high mode and then enter a new scan range - without recalling any presets before hand.
If you can't reproduce the problem I'll post a short video of what I do when it gets into this state to show what happens if you want.