That's not quite the correct way to set a laser, or you explained it badly.

You don't set it for "the top of the lob" as you put it because as you just said it will be low both short & long, you should set it at your zero range so that short it is high of POI & long it is low of POI, thus it is both an aim point & range finder

Laser designators are designed for fast target acquisition in close combat where body mass is your target, why anyone would use one when they have a zeroed scope which should be more accurate is, frankly, beyond me.