The "SJ", "SL" rating is the PQIA API rating for what the oil is supposed to perform. Each rating from the past till present is supposed to be better in total for engine wear, MPG, and other parameters. The problem with the most recent ones, SM, SN is the anti-wear properties, specifically the catalytic converter destroying ones ( mostly ZDDP "zinc") are limited, and reduced from the previous ratings. This is why you are seeing molybdenum, Titanium, and other exotic elements now in oils!
Helpful graphic:

Cam on bucket engines really suffer when this is reduced cars from the 50's and 60's have problems with wear when low on zddp, you can even buy it in a liquid form to help with older engines.
The Honda PCX uses roller bearing cams and roller rockers, reducing friction, reducing wear. And since we do not have a wet clutch, a MA rated oil is not required.
These reasons are why some of us freely state, use whatever 10W30 oil you can find, just make sure it is quality, and meets or exceeds Honda's requirements.