Just use te arcade_15 preset. The ms929 preset was created to make use of the 24 kHz range, but this only works for the autoswitch model.
However, in this case it's the JPAC the one that doesn't like the signal, probably 24 kHz. To properly diagnose this you should be able to tell which frequency is being sent to the JPAC at each moment, by looking at the video mode that's being used. Once you know that, you could adjust the range until both the JPAC and the monitor are happy. But anyway, I wouldn't bother, unless you are sure you have the autoswitch chassis.