2017 High Voltage Battery health

Hello Volt afficianados. I have had my fully loaded 2017 Volt Premier for 6 years. It now has 32K miles on the Odometer, 90% of which were electric miles. I am trying to evaluate how well my high voltage battery/charging system is holding up after 6 years and have a question about the 10 yellow/green charge cells on the left side of the speedometer. When I charge the car to "Fully Charged", all of these 10 cells turn yellow/green. Then, as I drive, the cells decriment one by one until the yellow/green color goes away in all of them and I am left with 10 empty cells and a Zero charge. Assuming driving at a steady speed and level elevation on a constant 65 degree day, would these cells decriment at a steady rate? Let me try and ask the question another way: If I were to drive on a hypothetical flat road in 65 degree weather at a steady 30 miles per hour and the first cell empties after, lets say, 6 miles, does that mean that the second through tenth cell will continue to decriment at the same rate--in this example every 6 miles or would the rate of decriment vary even though all the external variables remain exactly the same?

I am trying to use the above test as a way of evaluating the health/strength of my high voltage battery. If there is another better way to do that, I am all ears. Thank you for your collective wisdom\Rbon