Regardless of where the post is in the ring, I still think that if the rifle is zeroed with that sight picture/sight alignment, it will remain zeroed as you walk thru the elevation scale.
I know this as when I used to shoot free pistol with contact lenses, each time I put those lenses in my eye, it would affect windage. I would go to the range and have to slide the sight right or left quite a few clicks. But once set up, it was perfect the whole day.
Same for using simple aperture and post sights. I have used those different sights in BPCR. The rear is a vernier scale for elevation, the front is a "globe" sight with different inserts. Some are simple post, some a post and ball, there's a crosshair front sight insert and others as well. With the simple post, the top edge of the post was nearly centered in the front ring, but with the post and ball, the ball was definitely above the center point of the front ring. Shot that thing in silhouette tournaments for several years and had no issue having to change come ups using the same load.
Even if the post were above center or below center, with the ring in a ring and the post under the target, once adjusted for this sight picture, you still have a zero that is repeatable at any distance, taking into account changes in the elevation dope on the rear sight. If the post is displaced left or right of the centerline of the bore, you will have windage shift with changes in distance.
I feel comfortable the the OP concerns are not valid, based on my experience.