Apple Watch 9 fails to provide accurate swim details

I really enjoy my Apple Watch and it’s mostly accurate information regarding swimming laps. However, I don’t understand why it doesn’t record all of my laps… For example, today I swam 20 laps at 50 yards each (25 yd pool). It should have said 1000 yards total but instead, it only gave me credit for 975 yards. (no, I did not get out of the pool at the other end of one lap and walk back). It does this on regular basis. What changes can I make or do differently so that it records all laps not just most laps.