OMO deals with an abusive jerk type of mc who never see and the grind leads to sex with mom who the mc dominates, plus a little extra with a classmate girl. So it has a much longer grind part (not really that long, it easy to make up those numbers, 290 points required to see everything).
OML uses the exact same background (literally), just instead of domination, MC is a good guy and "charms" the mom and it is much much shorter with no sex yet. At 50 points mc takes her out for a date, where mc is revealed and a kinetic novel scene triggers that includes more line than what OMO has altogether pretty much. Mom and Son chitchats before they go home, a little non-sexual flashing occurs at the car and thats the end of content.