Quid
There is wiggle room within 91.129. Remember a VASI is just that, its not part of an ILS system, thus no OM or MM associated. As such on runways that don't have an associated ILS there is no way stay on till the MM. The reg states that the aircraft should remain an altitude at or above the glideslope until a lower altitude is necessary for a safe landing. Going into a place like John Wayne airport(5700ft), many find it necessary to go below to plant it in the TDZ. Its hairy in a NG let alone a 757 on a rainy day Many conversations with inspectors and our companies POI have led to an emphasis on the part of the reg that reads till a lower altitude is necessary for a safe landing