That worked Paul. It blows my mind that we we were able to concatenate two time strings with simple switches, but to simply use time as itself in a field required a paragraph of formula. (mind you I haven't tried this in the actual report yet ... it may behave quite differently)

How can the A or P for AM or PM be added? I tried the standard method of formatting but it came out looking like this ...

9:30九P -10:00九P

{IF{MERGEFIELD r1_relchg}<> "" "{MERGEFIELD r1_srl \@ "h:mmA/P"}-{MERGEFIELD r1_sru \@ "h:mmA/P"}"}