Differential (multielement) lumped ports in RF module

Hello,

I am using the differential (multielement Lumped ports) ports of the RF module to run an S-parameter analysis on a couple of differentiaol traces on a PCB.

Under Settings the reference characteristic impedance is set as Zref = 50 Ohm. Is that a differential or single-ended reference impedance?

I am doing a port and frequency sweep to save the S-parameters over frequency. Are saved S-parameters differential?

Thank You