Freelap reliability

Hello. I’ve seen some differing opinions on free laps accuracy for fly 10s, 20s, and 30s. I’ve gone 1.95, 1.92 for 20s, 2.97, 2.98, and 3.01 for 30s, and .96,.95 for 10s. All 20m run in on freelap. Should I take these times with a grain of salt or seriously? Additionally is there any predictors for 60m or 100m based on these fly times? Any thoughts are appreciated