Frank,

I would say yes it adds tolerance to the surface area. In comparison, many times with sheet metal stamping we See "Distortion allowed in this area" when forming metal brings together multiple surfaces. Meaning the primary surfaces must be held within the profile while a specified section of the surface is allowed to vary.

Geoff
Sr. CMM Programmer
Lapeer Metal Stamping
LMS Metrology Lab
Lapeer, MI