I think it has less to do with simplification on the NFHS part as much as the AFD in the NFL has to do with wanting to generate offense. The were far less AFD in the NFL in the past and it has gradually increase to the ridiculous level we have now. The NFHS has not followed suit to help insure a better balance between the offense and defense.

But the value of an AFD depends greatly on the down & distance to go. If the NFL wanted to do that, why wouldn't they use a more consistent method like increasing the distance of the penalty on the defense?