Although my pace reduced towards the end I felt that I had reserve but not enough to accelerate past the swimmer in front. For the last 2 sets I was pausing after each length to let him pull away and then catching up by the end of the length. I didn't have enough power to accelerate past though. So you could look at this as either I could have been a quicker, or, even though I was a tiny bit faster than last week I didn't feel as tired. Either position shows a gain.
Incidentally, to be fair to the swimmer in front, he didn't have a pull buoy to help him along. So he was doing 2:18min/100m for 1500m or so whereas I managed a best of 2:29min/100m in my 200m set.