In a conventional airplane, the lift of the horizontal stabilizer is subtracted from the total lift, not added as someone stated earlier. The higher the wing's AOA, the greater the subtraction.
That's only in cases where the designer hangs the center of gravity well forward of the wing's center of lift for highly stable stall recovery. Check out Section 6.
This only changes the situation by degree. All properly designed conventional airplanes will have the Cg forward of Cl, just some more than others (some MUCH more!). So in cases where the Cg and Cl are close, the horizontal stab does not need to pull the tail down with much force to change the pitch. But it still pulls down some, and still subtracts some lift. The amount of down force needed could be calculated as the ratio of the distance between the Cg and Cl(wing) and Cg and Cl(stab), with smaller Cg/Cl(wing) and larger Cg/Cl(stab)trending the downforce lower. So if the tail is long or Cg/Cl close the airplane is more efficient.
Jimbo
