Hi Emma,
I am using a consultant (probably the one you are speaking of as the pricing is the same as you mentioned) for my first reno business project in exactly the way you described. I nominated a budget I had to work with and was then provided with an action plan for my project and inturn this cuts down the time required for me to make all the selection decisions, takes out the emotional side of things and has freed me up to do the shopping around for the required items. I also have access to the consultant via phone or email at anytime throughout the project as it progresses. So money well spent.
Cheers,
Helen