No Kevin, I don't think you have fully understood what to do.
If you multiply Cp by 0.5*rho*V^2 you will get the pressure difference.
The pressure difference will be positive on the lower surface and negative on the top surface of the wing.
The pressure difference is the applied pressure in Ansys.
Since the surface normals for the entire wing are outward normals, a positive applied pressure will point inward.
That means the positive applied pressure on the lower surface will point inward (upward) and the negative applied pressure on the top surface will point outward (upward).
These applied pressures will have the effect of deforming the upper skin outward, the lower skin inward and bending the entire wing upward.
You can see the arrows in Mechanical when you apply the pressure to confirm the direction is as expected.
Therefore you should not have to change sign on any of your pressure differences.