Honestly I think often B and C scoring is a crock. If you want to improve the herd you shoot the deficient Bucks and not the best Bucks.
I generally cull them in the second year, old enough so you have an idea of what they may turn into and big enough to provide a good portion of meat.
I have a buddy, with a large lease, who has over a hundred trophies he has taken over the last couple of decades, his lease has nothing but runts now. The only time he ses a good Buck is when one of his neighbors Bucks wanders in during the rut.
My lease now is relatively small, but has some deep old woods with hidden glens, bordered by farmland. Many of my Bucks are exceptional. My Doe's run half again as large as my buddies Bucks in the same age group.
I'm not against trophies, but seriously the mid aged Bucks aren't the place to hunt IMO, inbred, obvious culls (knock knees or deformities) or aged Bucks are the ones you want.
IMO there is smart hunting and trophy hunting. Sometimes they are the same, most times they aren't.