Nike and Δ (?)

BITHYNIA. Nicaea. Severus Alexander. Æ 19. A.D. 222-235. Obv: MAYPCE)VAΛEΞANΔPO(CAV) or similar. Radiate, draped and cuirassed bust right; countermark (1) on bust. Rev: NI-K-AI-E between three standards, (ΩN) in ex. Countermark (2) on lower half. Ref: BMC 101 (?). Axis: 30°. Weight: 3.12 g. CM(1): Δ (?) in circular punch, 6 mm. Possibly Howgego 788 (62 pcs). Note: None of the coins recorded by Howgego weighs as little as 3.12 g., which makes it likely that countermark (1) is not actually Howgego 788. CM(2): Nike standing right, in oval punch, 7 x 8 mm. Howgego 255 (39 pcs). Collection Automan.