Whatever is reported has to be within limits, if they report only touchdown then that is all that is required. I believe that (not certain) to have a CAT III system approved you need to have multiple RVR reporting systems (certainly required for 125M TO).
There are a few weird places, RIX being one, where they used to have a CAT III ILS and therefore MRVR but since downgraded to CAT I but still give you all three on approach in poor weather. As they report all three you must have 550/125/75.