[FJames]

The math is simple: the total light output required to deliver the same screen brightness is strictly a function of the relative screen area. The Aura/Glow screen area ratio is 1.28:1 (Aura has about 28% more screen area). The both use LEDs which should be of similar efficiency, and the number of them doesn't really matter compared to the total light output. So the Aura with about 2x the battery capacity should last more than 50% longer at the same brightness.

Of course since the comparison tests don't seem to include any actual light measurements, and the percent scales are not necessarily equal, we can only assume that they adjusted the light to some personal standard of comfort. That might have been quite different between the Glo and Aura tested at different times.