... since we normally use POP talking about the city of puerto plata ...
You might. "We" do not. "We" use "Pto Pta".
"POP" is a useful abbreviation for "Puerto Plata Airport". Since the city already has its own abbreviation, why confuse them? It just leads to precisely the sort of confusion we see above.
I am disappointed in you, dv8. I have always regarded you as a crusader for accuracy here.