Why do LFP packs still taper so hard after 80%?

I daily an LFP car and love the charge-to-100% advice, but the taper above 80% still surprises me. On a 150 kW charger I see maybe 40 kW by 85% and under 15 kW past 95%. Is that purely a voltage-curve limit, or are BMS margins and cell balancing eating the headroom? I get that LFP has a flat plateau, so the BMS has less voltage resolution near the top. But does anyone know how much of the slow finish is thermal derating versus deliberate conservative cutoffs? Curious whether newer LFP chemistries and better BMS algorithms will actually fix this, or if we are stuck waiting 40 minutes for the last 10%.