Last two posts... Golf and Dom, now we're coming full circle as this all relates to most HS level players. Thanks for connecting the dots more eloquently than I have.
Additionally, at the HS level, if you "teach" level, most often the hitter's eyes tracking the ball will cause an automatic physical response that results in the desired slightly elevated path.
And yes, some are swinging down and they think they are swinging level. Some are swinging up and they think they are swinging level. So a quick video clip of themselves and some reverse instruction usually gets them going in the right direction.