Why are absolute/excess sorptions calculated consistently?

[Z.GAO]

Dear Prof. Dubbeldam and RASPA community,
When calculating the adsorption of propylene in MOF, I set the porosity in the input file. However, why are the values for absolute and excess adsorption still the same when helium porosity is set?
Below is my input file.

Best Regards!
Z.Gao

[David Dubbeldam]

The values are not the same. Excess is slightly smaller.

In the limit of low pressure, excess and absolute adsorption become equal. They start to deviate at high pressures.

Make sure your 'propylene' definition contains the proper critical temperature, pressure, and eccentric factor such that the Peng-Robinson Equation of State can compute the conversion properly.