Interesting. I hate the white theme of both iOS and Lollipop so I modify my themes as much as possible to get dark themes. At least in the case of Android this means that I am probably getting a brighter screen since I have a lower APL. In practice I notice my Note 4 screen is much brighter than my ip6+ when viewing it in full sunlight, although they are both readable.
It's interesting how this is an inexact science, or at least has to be quantified with the APL level, or less specifically with the particular app that is open when testing.
Lastly I wonder if this has any bearing on Googles piss poor decision to make everything so much whiter. It means less peak brightness, but also means reduced battery life on AMOLED. I wonder what the specific reason Google chose so much white.