Well spotted, that text is way too small for my eyes to see so I probably should have grabbed a screenshot and had a closer look, I was sure that the lower left was showing
Hold and the lower right was indicating
Low as in the battery is flat again.
Another look at their video linked below shows that the high and low are only displayed for a second or two at 0.29-0.31 so the readings are not held as would be the case with a dedicated Min-Max function, with a bit of luck they should be able to address and fix this feature in the application otherwise the high and low indication on this gadget is just plain silly.