The two highlighted settings under Folder Options are probably what you're looking for. Maybe they are set differently in your Opus 9 and 10 configs:
(They're described in detail here.)
Try changing them to suit the type of sorting that you want, and if you get there you can follow the steps in Folder Formats: Quick Guide to make that the default settings for all folders/windows.
If you can't get what you want using those two settings, could you give a few example filenames and how you want them to be sorted?