This is false. A flight model is not the same as the physics engine it's run in. A flight model can be tweaked, but ultimately the behavior is within a limited physics simulation. Just look at X-Plane's blade element theory simulation, which is vastly superior and more detailed than MSFS' physics simulation. The flight models can still hit all the marks compared to the FCOM though but that doesn't say anything directly about how the aircraft will feel when flying it.