The hash marks are there to help the oil stick to the dip stick long enough for you to check it.

The max dot (or hole) really is the maximum level, not the top of the hash marks.

If it's just a millimetre above the max dot, that's fine. If it's much over that, it can cause problems, some serious. A grossly overfilled engine can see oil pushed up into cylinders and burned with the gas, for example.

The beauty is, it's a simple fix - just let some out.