We were off by few in one of the crosschecks for a while. Turned out to just be voided mail-in ballots that in-person voters dropped off, which aren't supposed to be counted in the respective field. Which the manual doesn't really state (but one can infer it, it's clearly to ensure the total number of unused + used in person ballots match the supplied ballots). That manual could use some tightening...

I do quite like that permanent residents like me are allowed to be a poll worker in SF...