Your interpretation is correct except it can also apply to "other" than Dwelling Units, see 210.7(C). The key here is, if we are using a "Multi-Wire circuit it is only one circuit.
![[Linked Image]](https://www.electrical-contractor.net/ubb/wink.gif)
Also the breakers do not have to be ajacent to one another, they only have to be on different legs or phases.
Roger
