Seem to remember something about this, NJE used to use a similar procdeure to allow greater landing weights on on of the fleets. PAPI's are configured to a certain eye height, and smaller aircraft close in and 2 whites/2 reds are in effect where a 146 should be.
It cost a small fortune to certify and it may be that the other operator is piggybacking on the process. Of course if thats not the case and its a non legit 3red 1 white approach then it comes down to pilot ability which is difficult to quantify its not necessarily unsafe.
Remember the Iberia A340 that went of the end of a 10k foot runway after "going for the numbers" in south america somewhere.