You're right I forgot to add that information, and do not use COUNT. This scheme does not recreate the order when records are deleted. If you have 4 records and the sort values 1,2,3,4 and you delete record 3, COUNT+1 will return 4 which still exists.
Instead use MAX and account for the first record in your transaction with something like.
(($row_newsort['num'] > 0)? $row_newsort['num']:1 )
You can do this at several points depending on how you set it up. In my case, I put this in the sort columns WA transaction field
<?php echo (($row_newsort['num'] > 0)? $row_newsort['num']:1 ); ?>
Just make sure the minimum value is 1 and unfortunately MAX+1 of a null set does not get you 1.