Decreasing speed from 275kts to 215kts IAS at the apogee equals roughly 4100 feet altitude gain from an equal energy perspective.
Taking into account that there are some drag losses due to g load and roll the 3000 ft climb match excellently to the altitude gain to be expected by trading speed for energy based on the given data points.
As noted above, it's a compelling argument providing the IAS information we are working with is accurate. Given "ordered" airspeed and "what it takes to stall" the measurement anomalies seem to wash out.
@BOAC, in re God help us all ...
Doesn't this take us back to why you must have humans on the flight deck and
in command? The PIC must be in a position to override discrepant subsystems.
Systems will go squirrely.
That said, I agree with you that this particular feature might profit from some rethinking. Having read what you responded to, it makes no sense to me for this feature to be enabled at high altitude cruise. The feature appears to be primarily designed for flight regimes near to the ground.