Trying to set up an iip3 sim for a mixer.  Confused by a couple of results.  I set things up according to rapid iip2/iip3 paper.  Set the LO harmonics to 3 and rf input signal to 3.  For qpac, set max clock order to 2.  Result is as expected.  Not, if I set max clock order in qpac to 4, I get about 5 dB better iip3.  If I increase the harmonics in qpss, results get a few db worse.  Any  guidlines on setting these parameters?

Using spectre qpss/qpac