I don't know what you are reffering to with Level of Service, but at my airline (737) we can use VNAV for all approaches, regardless whether it's a normal NPA, RNAV to LNAV minima or APV (LNAV/VNAV).
I don't see a reason why you wouldn't be able to use VNAV on any approach, if the procedure is coded correctly and VNAV is available...