RE: dump subprocedures

Now that I've been playing around with CEERTX and CEEUTX a bit, I've got a 
couple questions that I hope someone can help answer.

1.  The procedure that uses CEERTX is called frequently - for every record in a 
file. (ie, main in module1 reads a record, then calls sub-procedure1 in 
module2.)  Will calling CEERTX to register the exit procedure cause a noticable 
performance impact?  If so, more than using MONITOR?

2.  Is CEEUTX even necessary for normal returns?  Unless I wanted to unregister 
a procedure so I could register a different one before returning?

Thanks!  Phil