I just have the M1 Ultra for a day, and maybe I am missing something. 

I used the fine point blade to cut self adhesive vinyl on the light grip matte. The vinyl was 30x30cm and I started in the upper left corner.

With the suggested 80g the blade hardly scratched the surface, and I increased it to 100, 120 and 150. 

Only with 150g I had the whole word cutted out, which could be okay if this would be the force needed. But I am confused that the more to the left, the less good the blade had cut. I would have expected that the pressure would be the same in the complete working area?