Why does ScanTailor sort like that? And could it not?

[chapkachapka]

I'm working with a particularly complex text, which is broken down into different volumes and chunks within volumes which have different page numbers, and I've set up the filenames accordingly. It sorts in my OS as I'd expect it to:

1-a001
1-a002
1-b001
1-b002
2-c001
etc.

But in ScanTailor it sorts in an unexpected way, where it does see the first number but then skips to the last number:

1-a001
1-b001
1-a002
1-b002
2-c001
etc.

Is there any way to change this? Or can someone explain how the sort order works so I can rename my files to match? It makes the usually very useful "every other page" functions useless.