Cannot delete >985 users | WordPress.org

Ahoy,

Thanks for the plugin.
The title pretty much sums it up. Searching for inactive users (flag one without posts) works fine and lists ~20k users. Next, I mark all, and click delete all marked users->Yes, I really… OK-> ..very serious… 985 Users will be deleted.

I take it the this is already hinted at by the “<small>PHP allows you sent only 1000 input vars.</small>” But still, why can I list 5k inactive users or even all 20k and also mark all of them but then only 985 are being deleted?
Cheers

The page I need help with: [log in to see the link]