The attachment shows my results after grading 30 crystals for the Measurement Receiver. This is typically what I see.
Your plots are new to me. It looks like your crystal test fixture is the same as the one I use with one difference. I originally used mine with the PHSNA and didn't space the BNC connectors for direct connection to the MSNA so I had two short (about 18") pieces of coax in the circuit. I'm not sure what difference that would make but you might try it to see if it makes any difference.
The max level looks about right so the power level is probably OK but you could try adding an external attenuator, re-calibrate, and see what that does to the plot.
BTW, if you set the plot format (Setup > P) to one, the firmware will connect the dots and you will get a better picture of curve shapes.
Dave Collins - AD7JT