Albedo image map to color's Light Reflectance Value (LRV)
I am not aware of what LRV is and what is a usage of it. However, I can recommend using luma instead of simply averaging RGB values with equal weight:

https://en.wikipedia.org/wiki/Luma_(video)
https://en.wikipedia.org/wiki/Relative_luminance
Example of using luma - http://blog.simonrodriguez.fr/articles/30-07-2016_implementing_fxaa.html

Human eyes are more sensitive to green colors [1], that's why 16 bit (aka high color [2]) palettes, might prefer to use R5G6B5 format.
[1] https://en.wikipedia.org/wiki/Color_vision
[2] https://en.wikipedia.org/wiki/High_color