We did this tour in May , in the 4:00 slot. Unfortunately, we didn't see any elephants on the tour. At all. We were told that for the past few weeks, the elephants had all "called it a day" around 3:00. They knew it was close to their time to go inside, so they were just waiting by their gates. Therefore, most of the late afternoon tours weren't getting to see the elephants. When we got back, they had a lead waiting for us, and she gave us a single FP good for 5 people (but not for any Avatar rides). Not really a good substitute, IMO.
Because this was a surprise for DD who absolutely loves elephants, I decided to see if we could reschedule for our second AK day. They were able to reschedule us, and they didn't charge us for the second tour. We did the 12:30 tour, and saw 5 elephants that time, and they stayed out throughout the whole tour. It was great.
So, my recommendations: Don't book the last couple of tours of the day. And, if you have a tour where you don't see any elephants, they will reschedule you for free, but they won't offer it. You have to ask.