[Elecraft] S meter differences from K3 to P3

[Jack Berry]

When operating I see a big difference between the noise floor and signal indications between the K3 meter and P3 display. 
For instance, on 80 meters tonight I see a noise floor of around S2-3 on the P3 and a signal peaking just over S9.

At the same time the K3 meter is displaying a noise level of S9 and a signal level of 20 over S9.

Is that a calibration error, a result of settings that I have selected - or just the way things are?

 
God Bless & 73!
Jack - WE5ST