At the risk of repeating some of the other answers, yes, its common to have the overlap for thermal magnetic breakers. Or maybe I should say that its just sometimes hard to avoid.
Notice that there isn't any point in worrying about currents higher than the bolted fault current available at the breakers.
Most faults will be downstream, and thus have some length of smaller wire in the circuit.
So real world fault currents are frequently much less than the bolted fault current, unless there is a fault right inside a switchboard or distribution panel.
So a lot depends on what you are trying to achieve. Most places this wouldn't be a problem. But for emergency systems, or critical health care facility emergency systems, you would probably try to eliminate or minimize the overlap, or go to the tables Ron mentioned.
This is why there was such a fuss when the code requirement for selective coordination was added to the code. Fuses are much easier to coordinate and much less likely to overlap at high fault currents.
