that's OK. The new calcul is : "$start_owner=Floor(($rank_owner+count($groups) - 1)/$maxm)*$maxm;"

But using "last page" don't realy works : it's not the real last page...

There are some problems in preferences with access autorisations :
1° the last page takes the same result than the next page about records (but the possibility of using butons is good) ;
2° one time, with the next page, a record is duplicated (the last record of a page is duplicated in the first place of the next page).
3° when we use the prev page buton after the 2° bug, recordss are next recordss, and not previous records ;
4° groups can be duplicated if they are on two or more pages.

Problems are in "/preferences/inc/class.uiaclprefs.inc.php"
I send you a corrected file.
I hope that's good...

Maybe there's the same bug in others applications, I didn't test it...

New code is between /* Begin debug pages /* and /* End debug pages */

In fact, the source of these problems is that "start" wasn't used to create next records.

ps : sorry for my english, I'm better with languages of programmation ;-)