From PGM-II and onward, separate ignition timing maps for each cylinder were possible.
For PGM-II,... between 1000 and 1800 rpm the rear cylinder timing is retarded compared to the front cylinder to give a smoother idle (when the throttle position is less than 5%)
I will guess that this remained the case for later versions of PGM, but am not sure. I have no experience with the MC28.
This should be easy enough to check with a timing/strobe light.

I am not sure if any of Honda's PGM's do this, but,... I have seen examples where, due to the crankshaft twisting very slightly when under load, one cylinder is slightly advanced compared to the other at certain rev/throttle combinations.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...