"Our caompany procedure is to fly all approaches using the FMS as the primary source of nav if the RNP is achieved and " where available, monitor raw data" , this is referred to in the Boeing FCTM."
If you are conducting an approach using the FMS as the primary source of navigation you are doing an RNAV approach. The requirements for doing those are pretty much universal and becoming more refined as time goes along and the world converts to PBN. You're suggesting your company does conventional NPA's and if the signal is not available, no problem, we'll just use the FMS.
If you don't mind my asking, what country is your company based in? Also if you don't mind saying what company is it?