Mouse Move Relative To Screen Xys Keep Changing

[Qwerty]

I'm writing a macro and much of it depends on moving the mouse around the screen, I've set it to do so based on 'Relative to Screen'. The problem is every few minutes, 326,274 for example, changes its postition on the screen and so the mouse goes to the wrong place and I have to set the coordinates again. Does anyone know why this is happening and how to fix.

 

Thanks.