you are correct, Sir. I must say, as a retired engineer with time on my hands, I designed the aforementioned quarter. The top base is set to be the same height as either a square bridge or a scope base from the action centerline and yes, not much of a sight plane but it still aids in sight acquisition.
I use a term, "goldline" which the amount of visible gold fill from the bottom of the filed V to the square bridge and try to keep this around 150/1000 for good pickup and this is a determining factor.
But in this day and ag, I have to consider scopes. The step down from the top of the base is to provide clearance for a scope with 42mm objective. If the top base was extended back for a better sight plane, would need a smaller objective or taller scope bases (then the stock design for sighting both irons and scope needs more consideration. I use Talley medium scope bases when a round action.
To uplander01 point. The section mating to the action front ring has the same radius of curvature as the action, just set below, 50/1000 or so. This give a nice interface.
Anyhow, I appreciate the comments.
Steve