Backup only?
In case you have a GPS or R-NAV Approach you have no further overlay.
Saying that means it is not a VOR/DME or NDB/DME Approach that is flown in LNAV/VNAV +50 feet to the MDA. If the Approach is a approoved RNAV approach you have in the applicable cases a note on the Chart that the proceedure is published and as approoved Operator you can use the given mimima and do not have to add the +50 feet as per recommendation.
I hope it helps to clear that. If not go to the Website of the FAA and search for it, if it is in Europe then search the EASA pages and you get more detailed information, the wording however can be confusing to avaoid legal liability.