Year codes

Submitted by J.Stephenson on October 13, 2023 - 11:40pm

I have two Bulova Acutrons day/date up/down watches. Both have M9 date codes on the case back, yet both movements are date-coded N0. Is there any info on why this may have happened, or is this a common occurrence for early-made N0 movements? Or is this a weird coincidence?