I do it differently because I've gone to one too many weddings where I really wanted one cake flavor but got stuck with another because the bride and groom picked different flavors of cake for each tier. The problem with that is there is a vast difference in the amount of servings from one tier to the next, which means guests get one flavor or another, and they never get to pick the flavor they want (at least I never have). But if you think about it, isn't the whole idea behind having multiple flavors of cake so that you actually get to eat multiple flavors of cake? Because doing it this way, you don't get to. You just get to wish you had the other flavor! LOL
So I do what I've called the "His and Hers" cake. They get to pick 2 flavors of cake with 3 different fillings and it goes in the whole cake. That way everyone gets the same flavors on the plate and they are never board. And it just happens to look cool to boot.
Logistically, it takes a LONG time to build one of my cakes and it took a lot of trial and error to be able to split my batters by not only single cake weight, but 1/2 cake weight, and making sure the different batters bake to the same height in the same pans. I also make sure all my crusts are trimmed and everything is level and even. I think it looks bad when you cut into a cake and there is mounds of frosting covering up sloped cake, or the cake layers are totally unevenly split. Anyway, my price per serving reflects the extra work involved.
Thanks for thinking I'm on to something cool :D My clients really love it too.