Well, well. well.
Exactly the same here for my SOSB 160 entry.
N1MM+ says 51 mults . Yet ARRL says only 50 mults. And boy have I checked them and checked them again to the point of right-clicking on the little blue tile in the mults table and establishing that the stations that were the mult are all present and correct and correctly in the log I have submitted.
Ron GW3YDX - GW5R in the contest.
ps - Thanks to all members of the group who gave me points for my GW5R SOSB 160 entry and also worked me as GW3YDX on other bands during the event.