Unable to use GetNextNumberWithGapsCommit() on PSWLINSTMAX in PT8.47.07

We're trying to change the code which is used to increment the worklist instance number in the application package PT_WF_WORKLIST to make use of Getnextnumberwithgapscommit() on the table PSWLINSTMAX in PT8.47.07. While testing the code, we've observed that the function is expanded as "UPDATE PS_PSWLINSTMAX" instead of "UPDATE PSWLINSTMAX". The record definition is having the SQL table name as PSWLINSTMAX. This function works fine with all application tables but it doesn't work in PeopleTools tables.
Can anyone suggest that is there any other prerequisite on using this function against PeopleTools tables?