Most of the old concaved morgan pads that I have seen is to adjust it to fit up and down since they have the teeth in the metal I don't know if it can be adjusted like a 4 way or not really it has been years since I have seen one but as Rollin Oswald said it would be best to replace it with a flat pad because even though the convace pad was designed to make a snug fit most of the ones I seen shoot them it didn't fit the shooter right but with the flat pad then it might another thing I have seen a lot was the shooter would cut the end curves off the pad.
I also think it is just for gun fit instead of point of impact but this is only my opinion only.
Since you already have it then go ahead a play with it and adjust it so you get a good line up of the beads it might just be what the doctor ordered for you also.
I cut my teeth on an old 870 with an adjustable Morgan pad and I liked it. Once I figured out where to put it it never got moved. I could probably dig it out of the safe and still shoot it. Had it since 1973.
Where a gun shoots, its POI, is dependent upon where the eye is relative to the rib. Raise the eye by raising the comb and the POI will rise.
Guns should be mounted (make contact with the shoulder) in the shoulder pocket, the slightly recessed area of the shoulder just inside the shoulder joint. They should also be mounted with the top of the pad, the heel, even with the top of the shoulder.
Concave Morgan pads "cannot" be mounted in the shoulder pocket without the presence of a large tumor in that area. The tumor is required to fill the concavity of the pad to avoid its bottom point painfully jabbing you in the chest when the gun fires.
Where Morgans CAN be mounted quite easily is on the shoulder joint or on the upper arm. Neither location is correct and both introduce problems that cannot be solved without changing where the pad in placed, inside the shoulder joint, in the shoulder pocket.
The points on concave Morgan pads can be removed and that would improve it. The result would still leave a thin, hard and ineffective recoil "absorbing" pad. It would be better to replace The Morgan pad with a good flat pad (or a convex pad if one can be found that fits your shoulder pocket.)
Put simply, a correct shooting form cannot be used with a gun having an unaltered concave Morgan pad adjuster.
Morgan adjustment devices also allow rotation the pad but they are not designed to allow it. For some however, it is a way to make the best of a bad situation.