MP-Advanced Correction value for Fe oxides

Dear Admin,
I am trying to reproduce the correction value for Fe.
I want to make sure that I am doing correctly as in the paper Jain (2011).
Fe2O3: -1.7112 (exp), -1.8862 (theo_MP), 0.175 (exp-theo_MP), 0.4 (fraction of Fe in Fe2O3)
Fe3O4: -1.659571429 (exp), -1.84 (theo_MP), 0.180428571 (exp-theo_MP), 0.428571429 (fraction of Fe in Fe3O4)
FeO: -1.4097 (exp), -1.669 (theo_MP), 0.2593 (exp-theo_MP), 0.5 (fraction of Fe in FeO)
All energies are in eV/atom. Then I have used Linear-trendline to get the slope (by fixing intercept= 0). But I am not getting -2.733. The slope I am getting is 0.446!!
Can you please tell where I am doing the mistake?