I got the Breathonix values from japantimes.co.jp/news/2021/05/24/asia-pacific/coronavirus-breath-test/
And the Sensera values from Stewart Mackie, although I recall there being another source of it being 100%/98% but I can't find it atm. Considering his legitimate connections to TPS and NanoDX I would consider what he says to be accurate at the time of it being said.
As for whether you still need to do a PCR test after the NanoDx test, I found this example of the flow which doesn't indicate the patient needs to do any further testing. Would hardly take this as the official stance, but it's an indication at least -
