I always run 20s. My p.r is 20:15 and I ran around that time every race.
My races
1st-20:39
2nd race-20:35
3rd-20:26
4th20:36
5th-20:25
6th-20:15
7th-20:24
And my friend has a faster p.r but I beat him in most races
His
1st-23:00
2nd-22:22
3rd-22:59
4th-22:47
5th-19:36
6th-21:57
7th-21:22