Might be a good time to post your code as it is right now, I am sure there is something I am missing.
From the manual :
An unlimited number of subroutines may be used in a program. Subroutines may also be nested. In other words, it is possible for a subroutine to call another subroutine. Such subroutine nesting should be restricted to no more than four levels deep (12 levels for 17Cxxx and 27 levels for 18Cxxx)
So as long as the look up table block does not call a sub of a sub then you shoulde OK with 64 GOSUBS to the lookup block and back.