Is it just me, or is the SPO2 functionality pointless? It's consistently 8% lower than a medical-grade device, there's no way to provide it with a calibration factor to bring it inline for my particular body/physiology, and obviously it can drop if you roll on your arm, or your arm gets cool, or.... lots of reasons. So why have it? Why have it during sleep, when the only point of it is to monitor for accurate O2 levels. IT consistently tells me that my respiration rate increases overnight (by 5bpm) and my 02 levels drop to 83%, which would indicate an issue, but since you can't trust it...