I think we're in violent agreement about what's usual. The question was raised of when flap modulation on final might be a justifiable or documented operation. Well, one such operation involves the demonstration of what's possible in unusual circumstances. And, as a previous poster noted, we don't actually know if there was an element of that in the operation described by the OP. (Maybe he should pick up the phone and ask, then put us all out of our misery!).