Some transformers, like the tester and the testfilters, gives you an simplified version of the expression you currently have in the "Composite Expression" by representing each clause in the Test Clauses table by its respective row number. This may help you in reviewing your tranformer, but this may also become hard to understand if you have a lot of clauses included because you have to manually count the rows in order to locate which clauses the numbers refer to.
I suggest that we should be able to show the row numbers within the table itself.