creo4 config.pro option documentation for: MAINTAIN_LIMIT_TOL_NOMINAL 
maintain_limit_tol_nominal
no
*
, yes
, tol_table
Maintains the nominal value of a dimension regardless of the changes that you make to the tolerance values.
no
*
- Changes the nominal value of the dimension when you modify the tolerance.
yes
- Does not change the nominal value of the dimension when you modify the tolerance.
tol_table
- Does not change the nominal value of the dimension when the tolerance of the dimension is driven by the tolerance table.