i think a lot of the confusion is caused by people assuming the angled CR surfaces are boundaries... in most cases you wouldn't design the control room with angled boundary surfaces unless you had to. most designs tend to put in angled treatments so you have enough space behind them for trapping and you use panels, slats, absorption, etc on the angled surfaces to shape the space to get a proper response from baffle mounted speakers, RFZ, etc. in a live room, you can more easily get away with the angled boundary walls because asymmetry in a live room can be a good thing.
as far as angles top-to-bottom and in-out, it all depends on the amount of space and what you're trying to do... for a small room, tipping the walls out at the floor can help preserve floor space, and since you're likely making the walls pretty absorptive anyways, you're not likely to deal with strong reflections because it. if you have enough floor space, tipping them out at the top can be useful to get things moving up and into overhead traps. all in all, the amounts of different angles you incorporate into the surfaces can move the sound into more oblique angles and potentially increasing the effectiveness of absorption in the room - at the expense of increasing the complexity of the construction...