Thank you for running this test. Your data is exactly what I had measured:
Input signal, U1282A measured
29MHz, 29MHz
30MHz, 30MHz
31MHz, 77.5MHz
32, 80
33, 82.5
34, 85
35, 87.5
based on your 32, 80 I expect your meter would behave much the same at the other data points. I think the meter displays zero once I took it above this. Sorry, I didn't write it down where it actually stopped doing anything.
Sad to see CEM of all companies actually putting something similar in their spec and surpassing it while Keysight.....