Are you lining up on the dot, or on the top edge of the front sight?

If the sight has a strongly-visible dot, the maker probably assumed that you'd line up on the dot, and calculated front-sight height based upon that.
But if you use the top edge of the front-sight blade, the way most people are trained to do, you'd be shooting low.

My P45 (same gun) has meprolights NS ...........I was shooting left sometimes but found it was me..............it is a tack driver..................Handall JR also helped.

the front sight has a white dot, and the rear sight has a notch with a white post down the center, without thinking or shooting it first I would put the white dot on top of the post. To shoot bulseyes I have to line the bottom of the dot with the top edge of the rear sight leaving quite a gap between the post and the dot. as it is right now the top edge of the rear sight is black, hard to see, although I could paint it. I can shoot small groups if I line them up like i said and let them go low, if i try to line them up to compensate I cant really do it consistantly, its just to big of a gap between the post and the dot, for my liking