Mate, I dont want to sound irrational, but that's the most absurd notion i've ever heard: to move FROM industry TO consulting for better work hours???
I work for Accenture, and what you have just mentioned is almost 100% propaganda and image branding. The hours depend entirely on projects and grade. A manager can work anywhere between 8 (in low season) to 20 hours a day. and trust me no one comes and tells you are working too much! lol, they might offer you an extra day off when the project is done, or a sumptuous dinner at an exclusive restaurant.
you can always try to work 9-5 but then a) you wont be successful b) you will see the more 'out' side of up or out
I dont honestly know of a proper company in any industry where a manager will work less than 50 hours a week, (except maybe for honda but then again a 40 year old manager will earn 40k).
a manager in strategy consulting will probably work closer to 70-90 hours a week on average, and salary will be from 70-140k.
remember its the last grade before partner, and a lot is expected of you.
hope this helps