I asked around a bit. Most but not all are fine with 4, with 3 being the minimum required.

Just follow directions. It's not difficult.

I don't think all Ortho applicants are so short sighted that they can't "just follow instructions".
But I honestly do not understand what it means when the program writes:
"Your application is considered complete when we receive at least 3 letters of recommendation". And that's it. Nothing more, nothing less.
So I wonder, do they mean they want only 3 or do they need more than 3.
This is not clear to me.
Any thoughts on that?

Then send 4 and see what happens. This is a perfect example of over-thinking it.

I agree: follow instructions. If anything, it's to most people's benefit to submit fewer letters.

For example: let's say you have 4 coins in your pocket (penny, nickel, dime, and quarter) and someone asks you to present 3 of these (of your choice) to give the best average impression of your wealth. Why in the world would you also show the penny? The only exception is if you have FOUR letters from VERY well-known persons and so the penny becomes a trump coin instead.

Remember that you have a choice of which letters you send. So, for instance, you're applying to a spine-heavy program and a joint-heavy program. You might, therefore, want to bias your letters for the recipient. Adding another would only serve to dilute your application.

The problem is I don't know which coin is which.
I signed a waiver and never saw my letters.
It is hard to predict who wrote you a 25 cent letter and who wrote you a penny letter. So by showing all the coins I have more chance of showing them the quarter, than if I showed only 3, and there is a chance that the quarter will stay in my pocket. The same goes for the penny.

Some medical schools will let advisors or deans read your letters and advise you which ones tend to be your strongest letters...

Not my school.
Thanks.

How often to people submit the max of 4 ortho LORs versus the required (most often 3 it seems)? I just ask because I might be scrambling to get a strong 4th...