Roman Empire, Probus, Antoninian Roma

OBVERSE: IMP PROBVS P F AVG
REVERSE: ROMAE AETER
BUST TYPE: H2 = radiate bust left in consular robe, holding sceptre surmounted by eagle (scipio)
FIELD / EXERGUE MARKS: -/-//R≤≥Δ
Note: RIC lists these coins with R-><-A (R thunderbolt A),  RჲΓ (R wreath Gamma), RჲΔ (R wreath Delta), omitting R thunderbolt Delta.
R thunderbolt A is most certainly a misreading of Δ for A, since hundreds of such coins have been attested from hoards as being from officina four. Meanwhile, I have never come across a specimen with Romae Aeter from officna one (R thunderbolt A). Officina "A" in the last emmissions before the coded eqviti series officina A only struck Victoria Germ reverse, not Romae Aeter reverse.
Thus, rather than a variant, one can catalogue coins with R-><-Δ as either RIC 183, ignoring RIC's mistake, or as RIC 183 corr.
Thanks to Grzegorz Kryszczuk for the above observation.