In your example, it already saved over #1 and #2 (Since #1 is older than 2 it sits below)
And #3 will get overwritten on the next autosave (or if you customzoi/edit appearance).
It is because they are sorted by last modified date.
No, not really. Think of the numbers more like “originally created first”. AutoSave #1 was named before 2 and 3. They’ll continue saving exactly in that order, but their titles remain the same which looks confusing. Like Samuriko said, the next time it auto saves, it will pick AutoSave #3, then they’ll be in the correct order again.