Wio 650 Battery Full Capacity 580?

I got a brand new Wio and the 650mAh battery, but I notice the battery status “Full Capacity” only shows 580. I have gone through a full charge / discharge / charge cycle, and the number actually went down. What am I missing? I set up the code with lipo.setCapacity(650) but a brand new fully charged battery only shows Full capacity 580.