Here is another thought.
For every single subroutine, you can have unique set of line numbers
inserted into each subroutine  for the whole application.
I now do this with MZTools ( www.mztools.com )
I use the line numbers for my error trapping section in each subroutine, along
with the subroutine name stored in a local variable in each subroutine.

Question is this:
At entry point of each subroutine, is there a variable that knows the total
numbers of lines in it ?
If so, you could take this total number of lines as the limit number and
calculate the %(percentage) for the progress  bar.
This would show the progress bar  from 0% to 100%, for each subroutine entry and
exit.
Is this possible to do ?