For the most part, yes. I had a time or three that the corals didn't look too happy, but by lunch time they were fine. I'm not sure what the tank you're talking about looks like, but I didn't have any fans on mine, which in retrospect, I'm sure would have helped.
It was fine during the week when the A/C was on...but over the weekend, they turned it off...so Monday morning my tank would be on the hot side...
I would drop in the frozen bottle and leave it for five minutes or so...then take it out for 10-15....then drop it in again, etc...until the temp came down.