Why do I get different shell thicknesses after extracting mask, even though I keep thickness setting the same?

Apologies if this is a dumb question, but I’ve searched the forum and can’t find an answer.

If I create a mask on an object, and then extract a shell, I get a shell with a certain thickness. However, If I duplicate the original object, then scale it up using the gizmo, then bake the scale in the gizmo settings, then apply a mask and extract a shell, even though the shell thickness number is set the same, the shell I extract is a different thickness to the first one.
I don’t understand why the shell thickness is affected by scaling the object first - especially as I bake the scaling in the gizmo settings?
Example: Here I’ve taken a plane, masked it and extracted a shell with the settings shown

Next I cloned the original plane, scaled it up slightly along the x axis using the gizmo, baked the new scale in the gizmo settings, masked the plane and extracted a shell, keepin shell thickness at 0.5, just like the first time; but here is the result:

The shell is quite a bit thicker than the first first one

I’d appreciate if someone could explain what’s going on and how I can produce shells of identical thicknesses, regardless of whether an object has been scaled (and baked) at some point in the past. Thanks.

Unfortunately you can’t for now, the thickness slider is not absolute.
In the future I’ll probably make it absolute in world space.

(technically right now it’s 10% of the mesh bounding box radius, so not really useable for precision).


Ok, thanks for explaining.