X-plane doesn't work exactly like that.
http://en.wikipedia.org/wiki/X-Plane_%28simulator%29#Flight_model
That article in wikipedia is wrong from the start assuming Flight simulators take lift and drag in tables.
already in 1993 most of the flight sims calculated lift and drag.
The only thing X-plane does differently from recent flight simulators is comparing the 2D profile
given by the creator of the plane with stored 2D profiles in database to have aerodynamic specs (coefficient of lift and drag) and that system in itself is not really the best way to handle things.
Most recent military flight sims like ROF and DCS BS/A10 are way more accurate than X-plane/Flight simulator.