Though this 40%-80% (or 30%-70%) is true, I think the battery charge
indicator just displays this limited range. So a 80% charge is actually
shown as full charge by the charge meter and a 40% charge is shown as
zero charge.

Thus there is no reason to not show 100% charge in the charge meter.

25 km (16 miles) on this limited capacity battery is impossible on flat road.
The battery capacity is of the order of 1.6 kWh. So less than 1 KwH
is available from full charge. A 3500 lb car cannot run 16 miles
on a flat road on just 1KWh of energy at 20-30 mph.

The rule of the thumb is 2 -3 miles per KWH at those speeds for this
size car.