Moving the plant/manufacturing area?
A man's got to know his limitations! (If he is unsure of his limitations, he should ask his wife!) I won't be so quick to jump onto the expert-bashing bandwagon.
There is wisdom to calling in experts when a problem's scope exceeds one's knowledge. A decent planner WILL talk to the shop people and processes, etc. or at least watch them. These people usually have a good grip on how their jobs and environments could improve, but these suggestions don't always translate into an overall systemic improvement. If your consultant has been around the block a few times, he is probably aware of many things that you might not catch on your once-in-a-lifetime run-through. Consultants are like musicians: you pay for hours of performance in order to benefit from years of practice.
Any expert worth hiring will give a synopsis of the approach he intends to take. Also, as the customer, you should exercise your right to judge and question whether you think your consultant is on the right track. If the approach is sensible, it will make sense to you.
I grow weary of the "things you can't learn in school" diatribe (the mantra of the uneducated). I can usually throw that back with a "things you should have learned in school if you weren't sleeping" counter. In proper context and application, theory and practice NEVER contradict.