Sorting by profile field

Sorry as I think you may already know about this....

I have a members page that shows just two columns: 'Company Name' (a profile field) and 'Username'.

The sorting on the 'Username' column works fine. The sorting on the 'Company Name' column does not, where it sorts alphabetically fine for about 3/4 of the list, then does a couple of restarts on alphabetical resorting - in other words, multiple alphabetical lists.

I notice that if I edit a user, it drops it to a the lowest alphabetical list, so my guess is maybe it is sorting by 'date last updated' and then by Company Name. I added my users using a bulk import (user import module) so that is why there may be chunk of users within the same alphabetical listing (one chunk for each import date). Just guessing.

Looks like sorting is handled somewhere starting around line 958 in your module - but I'm afraid its beyond my skills.

Thanks for anything you can do and thanks for the module!