Inherited this code, is there a better way

Inherited this code, is there a better way

I have inherited the code in the attached doc. (tried to include it here but exceeded limits.), and, although I am very new to tablesorter, JQuery and AJAX, I can not help but feel that tablesorter is not being used quite correctly here.

The following functionality works as the developer intended: (line 667) (called on line 637. Function begining on line 661)
The double click functions (lines 648 through 659) (line 630)

All of this does what the developer intended. I am just not sure it is making use of tableSorter (line 358) and tableSorterPager (line 393) correctly. Here is why.
This code hits the DB for every sort by calling the function 'get_promo_code' (line 397in the tablesorterPager section). This seems to bypass what tablesorter is for.

Is there a way to keep all of the functionality I outlined above, but allow tablesorterPager to operate as intended for the paging and sorting? Or, because the call to 'get_promo_code' is needed for the 'Search' and 'Full Search' capabilities, am I tied to always making that call?

This is all quite new to me, so any and all help will be appreciated. Also, if anyone knows of a forum more strictly dedicated to tablesorter, please let me know. I know this is a JQuery forum and this is dealing with more than JQuery.