Why don’t my real-time metrics in the Ergatta app match the metrics on my S4?
You may see a discrepancy in the stroke rate and split metrics between the Ergatta app and your S4 monitor. This is expected, due to a difference in the time frame over which these metrics are calculated. The Ergatta app uses a more real-time calculation of these metrics to make it feel more responsive when you speed up to catch the opponent ahead of you, or when you adjust your cadence to hit new targets. For the SPM specifically - the SPM you see in the Ergatta app isn't actually incorrect, rather is more reflective of your real and current SPM output. The S4 calculates SPM as a rolling average over 7 strokes, which made the experience to some users feel too laggy. Over long periods at constant speed and constant stroke rates, you should see the two converge on the same stats.