I used the 16x100 in a 25m pool from TT1:30 to 1:00 desc 0:02 and these are my results
1:30-1:24 SPL 11
1:23-1:14 SPL 12
1:13-1:04 SPL 13
1:03, 1:02 SPL 14
1:01, 1:00 SPL 15 (last one on 1.10)
Almost all of the 100s were the first length one less then I had on length 2 & 3 and one more on length 4.
I guess the reason for the first length constantly being -1 is a better-then-average push off at the start. The reason for a +1 on the last length is that there is no turn, I wouldn't need another stroke if I do a turn.
The high stroke count on 1:01/1:00 may have to come from fatigue, I have had a training break almost a month before this session and during fall I did one session a week.
I'm a 50years old male 1,83cm tall.