If the broadhead arrows are longer than the field point arrows, you would expect them to impact lower if you are aiming using split vision. You could correct this by using a fixed crawl when shooting field points, unless this screws up your qualification for leagues or tournaments. It shouldn't take much of a fixed crawl to get them hitting in the same place, maybe 1/2”, which you can establish by experimentation.
Long term, I would probably change one or the other so all your arrows are the same length.