Recently the Stamps | Europe | Vatican category was changed to
Stamps | Europe | Vatican | Other, and
Stamps | Europe | Vatican | SMOM
This may make sense to a few Italian or Maltese stamp buyers but will confuse other people.
If you believed the stamps were real and wanted to list stamps for the Sovereign Military Order of Malta then you would want to list under
Stamps | Europe | SMOM
as does the only lister of these stamps on Ebid, but not as a subcategory of the Vatican.
Also bear in mind that these are Cinderella stamps which do not have postal validity throughout the world, unlike Vatican stamps. Ebid does not normally create special categories for stamp printers who are not members of the Universal Postal Union.
If you wanted to find Vatican stamps then you would probably not look under Stamps | Europe | Vatican | Other because Vatican stamps are Vatican, not other.
So I suggest you remove Stamps | Europe | Vatican | SMOM, and either create Stamps | Europe | SMOM or a better category for stamp collectors would be Stamps | Europe | Cinderella
and take Stamps | Europe | Vatican | Other back to being Stamps | Europe | Vatican