I heard that overseas and military ballots aren't actually counted.
Phooey on that! It is illegal to not count and include all ballots received in order to certify the election.
For a while now, Americans have bantered around the idea that overseas and military ballots are not always counted.
Mostly this confusion comes from the fact that elections are often "called" before all remaining ballots are counted. Sure, the media will rush to announce the outcome of the election, but that doesn't mean the counting stops!
The final count is what is certified, and that certification of the election can take days or weeks to occur. Election officials must reconcile all ballots. They know how many were given out, including those sent to voters abroad, how many are returned and how many do not come back.
The confusion can be boiled down to a simple math problem. When counting the ballots, at a certain point, if the margin for one candidate is greater than the number of ballots remaining to be counted, then it is mathematically impossible for the other candidate/s to win. The winner can be announced.
Later, when all ballots are counted or accounted for, the final ballot count can be recorded and the election can be certified.