Bangle.js 2 Cutting Edge - new heart rate algorithm

I have made a little test app that will record raw HRM data to a file, and allow me to vary the LED power by swiping the screen up or down.
The things I have found are:

1. The photodiode reading varies from 8190 counts (13 bits?) to zero
   
2. Increasing the LED current decreases the reading
   
3. The default current register value of 15 (decimal) is pretty good and gives a mid range photodiode reading.
   
   

As long as I don't try to plot the graph on the watch screen, I can log at about 40 ms intervals, and can pull it into a speadsheet to look at it:

From a visual inspection of the first 5 seconds, I can see about 5 peaks, which is consistent with my actual heart rate of around 60 bpm, which is encouraging. Unfortunately the watch is reporting over 100 bpm, which is not so impressive. It sounds like this is the opposite to what other users are reporting, as others are reporting low indicated heart rate compared to actual.

So I'm still not sure what to make of this, so I'm going to try to do the same on Pinetime and see how it compares, as I am still suspecting that the HRM sensor in my watch is not really working very well. If anyone else could try to collect a similar set of data on a different watch, I'd be interested in seeing the comparison of different BangleJs watches.
Thanks

Graham.