Service time = average of the difference b/t ticket.closed and ticket.created time in days. Thus if you multiply by 24, it'll give you avg. time in hours.
So what I did is this.
in the ajax.reports.php file where it says:
FORMAT(AVG(DATEDIFF(T2.closed, T2.created)),1) AS ServiceTime
I multiplied it by *24 to give me the time in hours.
FORMAT(AVG(DATEDIFF(T2.closed, T2.created))*24,1) AS ServiceTime
It's pretty much the same thing with the response time. Also, I changed the label too, to say "Avg. Service Time (Hours)". You've got to have units, for easy readability.