Hi Alitsu, ok I understand your point.
For WDM cases, I usually do not use Constant Dispersion parameters, but I use Disp vs wavelength from one of the files built-in in Optiwave.
You can try to use one file for the propagation fiber dispersion, and create the one for the DCF by simply multiplying each dispersion number * (-5). This should improve your simulation.
Let me know if this works.
Alessandro