I’m not sure I understand.
Nuendo has RMS Max metering. I don’t see an RMS max reading option in the Digicheck meter.
When I pump a testtone through the application, then there is a 3 dB difference between the Nuendo and RME readout.
Which is “solved” when you activate the AES17 option in the Nuendo meter.
HTH
Fredo