Definition of lift (2D): Total lift is the integral of the pressure, in the direction perpendicular to the farfield flow, over the airfoil surface.

For a given flow conditions of density, velocity, operating pressure, shouldn't the outcome of lift (given as report definition) and the outcome of computed value of 'integral of static pressure over wing surface' be equal?

The computed value of integral of pressure over the wing is always around 2 times the lift which is computed. Why is it so? I am not able to understand why this mismatch is happening. Please clarify.