Reflection coefficient from feko lua script

I use a simple example Dipole in front of the lossy metal cube and want to get reflectivit from a postfeko file using lua script,

for a simple script:
dataSet = pf.TRCoefficients.GetDataSet
print(dataSet) -- Describes the structure of the data
inspect(dataSet) -- Gives a list of the data set contents

i get a number
------ Running refl_coeff ------
function: 000000001DA49570
function

in postfeko it it 1.4 +j

in out datafile there is no refl. coeff
s11 is


SCATTERING PARAMETERS

ports magnitude phase
sink source real part imag. part linear in dB in deg.
S 1 1 2.44212E-01 1.89512E-01 3.09119E-01 -10.1975 37.81
Sum |S|^2 of these S-parameters: 9.55545E-02 -10.1975
Reference impedance in Ohm: 5.00000E+01

What is the right value and how to get it in lua(in a right format?)?