I was running some tests earlier and started sales invoices at 1.
I noticed that 10, 11, 12 appear before 2, 3, and 4.
I know that I can click the column header twice to get it into order (the first does a reverse numerical and the second an incremental numerical sort), but the first appearance appeared to be by alphanumeric order. it may have also been that I created all of these on the same day, I didn’t test against different days
My first impressions was that it would have been by time stamp or by invoice number, and then I just tried leading zeros and now I’m just not sure.
When I click on sales invoices, this is how it appears:
For info: the very first one I created was #1 which appears in the middle of the list