Mostly it’s bullshit numbers. A 1.5hp motor should draw around 14 amps on 110v. That’s pretty much maxing out what you should have on a household circuit. Manufacturers just like to make up things like “developed” or “max/rated hp” or other stupid terms that don’t actually mean anything but make their products seem more robust. Look at the current draw on the opener. The more it draws, the more powerful it will be.