The are just 'dumb' pre-programmed voltage levels, which means they are prone to being fooled by the unusual lithium battery discharge curve. The controller display on most bikes uses an algorithm to estimate the battery discharge rate based on the inputs of a number of variables. This is how they get a little closer to accuracy, but still has a pretty wide range of variability if you are altering settings and riding style throughout your ride.. All devices that are designed for lithium batteries need to have an algorithm that accounts for storage time/operating time/draw rate/settings, etc. to provide any kind of reasonable accuracy.
My bike and batteries have a similar issue, and they decline much later then the main display indicates. Once they do start to drop off though, they drop fast just as i expect. I know not to trust the battery LED's for range estimation at all. They just help me know which ones on the shelf are fully charged or not.
As an anecdote from my previous other life as a fire chief and mountain rescue manager, this was a life and death issue when lithium AAA and AA batteries became widely available and started to be used in avalanche transceivers. Lithium batteries were marketed and sold as superior in cold weather due to their voltage stability in the cold and their long storage life. However after a few fatalities where Transceivers failed very quickly after an incident, it was discovered that we were all unaware that the devices would show full battery until the last 10-15% of the batteries capacity, then decline and fail in a very short period of time. Some devices stopped transmitting right after a burial, and they couldn't be located by their friends, and others were doomed when their friends batteries suddenly 'died' right after they shifted into the power intensive 'search mode'. We soon received alerts and notices from the device manufacturers telling us not to use lithium batteries at all, and some other manufacturers simply added a new algorithm that used time since install and usage stats to estimate the lifespan of a set of batteries. Those devices had to be set every time you removed a battery to indicated if you had replaced them with lithium or alkaline, so it could switch between 'time' mode, or 'voltage' mode. Even then, we would often pull out lithium's after the scheduled replacement time, and be able to burn them off for a significant amount of time in flashlights and other less critical 'dumb' devices.
