Hello,
You can create an Entity to store the AutoNumber ID, creating the Object of that Entity and committing only when saving.
That way when you enter the page and exit anyway, it won't add a number to the ID.
An AutoNumber will always create a new next number for a new object, no matter what you do with the created object. It’s just a simple way of creating unique numbers.
If you really need to have sequential numbers without gaps you need to maintain them sourself.
regards, Fabian