Pico laser treatment outcomes - why would someone have a scabbed face versus not?

When I research PICO lasers and other peoples experiences and outcomes, it seems like there is quite a disparity between some people having virtually no down time-to other people having very red and scabbed over looking faces for many days after. I imagine that means the laser is at different intensities, but what’s the difference? Is getting PICO where my face isn’t red and scabby not as good and mean my results aren’t going to be as optimal? Why would someone have a scabbed face versus not?