The DOCU-ENABLE-TEST-FOR-DIM-CONVERSION function switches on or off a check performed when you convert dimension tolerances. If you try to convert a nonsymmetric tolerance value-pair to a plus/minus tolerance, which is not possible, Creo Elements/Direct Annotation will either check this and issue an error message (when the switch is :ON) or not do this (:OFF). By default, no check is made and the error message is suppressed (:OFF).