Address tagging in Hungary

Hello Hungarian mappers!

There is a single neighborhood in Budapest which now has almost all of the deprecated addr:staircase tags in the OSM database, here

In Finland addr:staircase was replaced by addr:unit, which matches the Finnish addressing system very well. In this case though, the entrances in the buildings in question have both unique addr:housenumbers and addr:staircases. Is the staircase letter part of the official address, so it could be perhaps replaced with addr:unit, or should the tag be ref=*, or something else?

I hope someone in the Hungarian OSM community could have a look.