I have a bltouch clone which work fine on glass bed. After switching to textured PEI sheet, it’s variance trippled to 0.1mm, which make my bed mesh all wobbly.
I’m I suppose to remove the steel plate when making the bed mesh? Do you home Z with a probe with this setup?
The weirdest thing is, despite all this all my prints adhere completely fine. I guess PEI is just that good.
Maybe clarify what you mean by variance - Samples in the same spot vs variance of min/max points? Temp can change things, are you keeping it constant between measurements and letting the bed heat soak at all? How does the first layer look? If it’s consistent you may be over thinking it