(a) Normal operations or statutory objective of any program or activity. A recipient is permitted to take an action otherwise prohibited by § 20.4 if the action reasonably considers age as a factor necessary to the normal operation or the achievement of any statutory objective of a program or activity. An action meets this standard if:

(1) Age is used as a measure or approximation of one or more other characteristics; and

(2) The other characteristic(s) must be measured or approximated in order for the normal operation of the program or activity to continue, or to achieve any statutory objective or the program or activity; and

(3) The other characteristic(s) can be reasonably measured or approximated by the use of age; and

(4) The other characteristic(s) are impractical to measure directly on an individual bases.

(b) Reasonable factors other than age. A recipient is permitted to take an action otherwise prohibited by § 20.4 which is based on a factor other than age, even though that action may have a disproportionate effect on persons of different ages. An action may be based on a factor other than age only if the factor bears a direct and substantial relationship to the normal operation of the program or activity or to the achievement of a statutory objective.