I agree with Shadorne's point, but I'd just note that there is (at least) one (kinda rare) exception to the high x-over point = beaming rule. Omnidirectional drivers (like those in MBL, Ohm, B&O, etc.) are usually designed with a very high "hand-off" from the mid to the tweeter, yet (due to the omni design) the mid driver doesn't narrow its dispersion pattern near the top of its passpand.
Marty