No not making it up, know better than that. Possibly heard it at FSI but for sure a few guys at my place claim (maybe they heard it at FSI) use APPR for DA's, and NAV for MDA's.
Take a look at this link, slide 14, and slide 26, the US Navy T-44C training also seems to advocate NAV for non-precision and APPR for precision.
https://docs.google.com/viewer?a=v&q...zzqCGPzffdeSXQ