[EV- Technician]

Dear Mr. @billcarter
In reference to the linear fashion of HV DC packs, as the state of charge diminishes during driving, the total pack voltage correspondingly decreases. Consequently, to maintain the same power output, a higher current is required compared to when the pack is fully charged and the voltage is significantly higher.
This is the reason for Bjorn's confusion. The BMS is actually using the remaining Ah to address the remaining SOC with other inputs on top of them.
If you require more accurate information on energy remaining (ignoring SOC altogether), I recommend using the Carscanner Pro app.
And the EV9 is not a true 800V architecture, and at a low SOC level, this is more evident because the SOC percentage is actually falling down more quickly (but it is accurate information, even if it makes the owner question the sudden changes in how SOC is related to the miles traveled).