@Rice-Eater probably not. It's very hard to draw any conclusions from a battery discharge curve the first 70% of the battery usage since the voltage will always be high during that time. It's only when the battery approaches its end of life that you can really notice that the voltage drops more and more. Also when the battery is stressed, like when the LED is on, the voltage temporarily drops even more. That's why we have chosen this approach to only show an icon when we estimate the battery is low.
Other more sophisticated devices such as smart phones use coulomb counting to accurately estimate battery life but we can only measure the voltage level.
That said, with the SDKs we offer we can still give you the actual battery voltage level in case you want to use that information.