What you may be looking at is a tuning issue. Maybe your nocking point is a little too high. You said your arrows are hitting lower than field tips. This could be the cause. You don't say how far below field tips they are hitting or at what distance, but I would try lowering the nocking point a little at a time to see if things improve. If they do then you're on the right track.

Now, this being done you'll also have to slide your peep and kisser down as much as you moved the nocking point. And probably gang adjust the sight also.For referencebe sure to take measurements of these things prior to any adjusting.

As for penetration, yes, if your arrows are planing or wobbling it can reduce penetration.