Neeraj,
Thank you for your post!
For discussion sake, if for report(s), the values of condition types ZPR1 to ZPR4 are picked from billing document, line item level (table KONV); then even if the above change is done (condition types made statistical), there would be no change in the report (output).
But if the values are picked from the accounting document (of these condition types), then certain changes in the picking / extract logic has to be incorporated.