It's impossible to know just how widespread a habitat range certain types of species occupy. What you do is, examine specimens from as many locations as is possible, then compare the results. Who can do this?
I've always been suspicious of Cribb's 'area maps' because I know he's never been there to cover the entire region, nor has Kew's collectors. What he's done is to show the outer range of where a species has been located, and then guess at the rest. His maps of P. lowii (and P. bullenianum, etc.) each cover a huge area, and they fail to allow for "discrepencies" within locally isolated "hotspots." As we make more investigations we then find these spots which at times, harbor distinctly different types, usually derived from ancestral heritage, and we name them as new species. P. richardianum and P. lynniae are two fine examples.
Cribb's (and others) refusal to accept P. celebesense as distinct from the type P. bullenianum is a case in point. I think P, celebesense can be distinguished by most all orchidists, from P. bullenianum, as can others in this same complex. The question then becomes, ... do we split or do we lump?
Herr Bundt, on Sulawesi, once told me there are two forms of P. mastersianum, one from Ambon, the other from Ceram. Well, I've only seen the one we know, and now, for the past 8-9 years, Muslims are actively killing too many Christians over there to take the chance to find out for ourself.
P. virens is easily distinguished from P. javanicaum The ranges are far apart and can be separated geographically, as well as can their individual habitats.
I could go on and on. Who can answer your question? I don't think we will ever know, particularly since the CITES debacle. Unfortunately!