Many loved maps have game breaking mechanics which the pp system will support less. Talking about stuff that will give x10000 pp than it's worth or something. Some loved maps are storyboard driven and so you would need the pp calculator look at storyboard to calculate difficulty. It boils down to figuring out the difficulty of how hard something is to read. If you can figure that out, then there is a chance loved maps can give pp and not be severely under/overrated.