Problem with calibrating modulus degradation curve


Hello everyone, I am currently calibrating the modulus degradation curve to a published curve, using the sigmoidal-3 model. Using the provided one-zone code in FLAC3D (One-Zone Sample Exercised at Several Cyclic Strain Levels), I get the parameters a=1.032; b=-0.517; x0=-1.758, which are similar to the curve of Seed and Idriss. However, when I plot the curve in Excel using the formula of sigmoidal-3 curve, it does not match at all. I wonder if anyone has also encountered this inconsistency?

Using those parameters, the Sig3 model shows consistent results, see the plot from Excel, you may check your inputs.

Thank you very much for the verification.
It seems in the sigmoidal-3 curve, shear strain in L=log10(shear strain) is not in the original unit, but is in percentage.