Using the same admin level for areas that are divisions of a larger area doesn’t make sense.
The administrative boundaries for overseas territories are not as well maintained as the ones in continental Netherlands because we have good reference data for the latter (BAG).
You should probably talk to Aleksandar Matejevic who added the Oost & West relations, he’s not part of the local community so YMMV.
Looking at the ways of relation 14034189 you can reverse engineer the broken relation that Aleksandar fixed in changeset 121381966, it has type=boundary name=Oranjestad Oost on way 1051307563, and those belong on the relation. The same goes for the other ways. Way 1058284863 has type=boundary boundary=administrative admin_level=8, and way 1062997228 only has type=boundary. The type=boundary tag does not belong on ways, only relations.
The wiki only defines admin_level=8 for “Districts (Municipalities) known as GAC regions”. The subdivisions of GAC regions should likely be considered similar to Wijken en Buurten in continental NL (they are not administrative boundaries, they use type=boundary boundary=place place=quarter/place=neighbourhood) that is a good suggestion for Orjanjestad Oost/West.
Oranjestad-West and Oranjestad-Oost are considered zones according to the Dutch Wikipedia, place=borough might be appropriate for these, because both are further subdivided in wijken & buurten (place=quarter & place=neighbourhood).