The only choice for an iPhone 6 Plus

I tried many heart rate monitor apps on an iPhone 6 Plus. Most of them failed completely while some worked once in every five or six attempts. I think it has to do with the protruding camera lens (due to the image stabilizer) and the large spacing between the flash and the lens in the iPhone 6 Plus.

This app is the ONLY one that worked consistently and was accurate when checked with several manual measurements of my pulse.

Yet it is nowhere in search! Why, Apple? This app should be the first result on a search for "heart rate monitor". Yes it isnt free but the free apps do NOT work.

Here are some of the apps that failed:
Instant Heart Rate by Azumio - a complete fail; did not work even once
Cardiio Heart Monitor - only worked using their face mode, which is inaccurate; finger mode never worked
Runtastic Heart Rate Monitor - worked intermittently; perhaps once in every five or six attempts

guybca about Sleep Cycle heart rate, v1.2.2