Easy test -
- Set UseExtrusions to Extrusions, make a box (extrusion) bigger than, say, 20 units
- Copy the extrusion to one side, Explode/Join to make it into a polysurface.
- Run the Mesh command on both boxes with the following parameters:
(set a max edge length of something smaller than the box, say 10)
The mesh made from polysurface box will obey the max edge length setting, the one from the extrusion won’t. This is particularly pernicious as it also affects all export formats(such as STL) that export meshes directly, you will not see the problem.