Hi,
My pool swim intervals come out ~1 s longer per rep than the lap times in the original FIT file. I have a Garmin Forerunner 265S (fw 29.05), 25 m pool, manual laps (lap button at the start and end of each rep), synced via Garmin Connect.
Activity i206024635 (20×50 m), first 5 reps:
| Rep | FIT lap total_timer_time |
intervals.icu interval |
|---|---|---|
| 1 | 44.4 s | 45 s |
| 2 | 44.8 s | 46 s |
| 3 | 44.4 s | 46 s |
| 4 | 45.2 s | 46 s |
| 5 | 44.9 s | 46 s |
Over all 20 reps: FIT average 45.8 s (1:31.6/100 m) vs intervals.icu 46.95 s (1:33.9/100 m). Every rep is longer, by +0.6 to +1.9 s (mean +1.1 s).
Activity i206441592 (12×150 m): FIT average 152.0 s vs intervals.icu 153.5 s. Every rep is longer, by +0.6 to +2.7 s (e.g. 149.9 → 151, 150.5 → 153, 151.3 → 154).
The difference is never negative. Maybe an extra sample is counted at an interval boundary ?
I am not sure what would be the fix. Is it something from my side, like a parameter i forgot ? If not, would it be possible to use the FIT lap total_timer_time (with decimals) for pool swim intervals ?
Thanks 
Melvin