SnP Files extracted from PSP simulation

Hi Cadence Forum,

I had an extracted sNp file after finishing psp simulation.
Howerver, after putting that file in an nport component, and running the sp simulation for checking. 
The S-parameters' response were different than those of the original psp simulation result.

Can anyone suggest why this discrepancy might be coming. I am using IC617 and Spectre 16.1 versions.
Thank you