In a
rare series like this one, I'd recommend keeping the poorer one too if you upgrade, as long as the two are not from the same die pair!
You write, "thought to have been minted at
Ephesus due to a similar 'o'
mint mark previously used at that
mint". I regard that as a clear mistake by Buttrey and
Carradice. Yes, annulets appear on some late
Ephesus denarii too, but everything else is against attributing this later annulet series to
Ephesus.
Ephesus had its own
reverse types, faithfully repeated from issue to issue. But the new series copies its
rev. types from
Rome, as you note.
Ephesus had its own
obv. legends too, usually dated with consulships. Quite different in the new series, again copied from
Rome. The
style is totally different. Errors, such as calling
Titus PON MAX and many
mules mixing obverses of one emperor with reverses of another, occur only in the later series, never at
Ephesus. Against these blatant differences, the shared annulets are I think a mere trifle. A clear case of different mints in my eyes! So "
Ephesus (?)" should be dropped, and we should return to "uncertain
Asia Minor mint".