SMM12 — SMM is presumptuous about how measurands must relate

In 11.2, 11.7, 13.2 and 15.3, the base model is presumed to be a MOF model which is too restrictive.

GradeMeasurement Class (clause 13.7) and RankingMeasurement Class (clause 13.9) have constraints requiring the identity between the measurands for the derived measurement and the input measurement. These constraints are beyond SMM's scope. Note that measurands are typically not defined in SMM, but in some other model. That other model (and not SMM) should, therefore, determine how measurands relate.
In 16.4, the sentence referencing "same measurand" similarly implies a requirement which is outside SMM's scope.
Furthermore, in 11.2, 11.7, 13.2 and 15.3, it is stated that measurands are declared in another MOF model, which is too restrictive.

Remove constraints and include text discussing measurand sameness

Relax constraints about sameness of measurand of input measurement and derived measurement. Rewrite and complement text that is about sameness of these measurands.