Sharraxaadda

Twice now this precinct has ballots start at 500, first time I saw it was 2020. In all the years of voting, previously in Sterling Heights before moving to Roseville, the ballots were consistently numbered identical to voter number, minus of course one or two spoiled ballots. Yet here they are starting at 500, where are the other 499 ballots at? Does Roseville do something different?