The point is that the wholesaler needs to understand how to arrive at a proper exit number for their intended or suggested scope of rehab work.

I don't know what kind of due diligence a turnkey provider does as far as inspections, etc. but I would advise getting a full inspection and a sewer line scope.

I tell them I need an itemized estimate on my scope of work.

@Tony Gunter  I did think that price was way less than I thought for the scope of work.  

While the phrase :You get what you pay for" does still apply when it comes to architecture, it is definitely more skewed as the Architect's scope can very greatly.I expect that as an investor you are likely looking for drawings detailed enough to obtain a building permit as well as get accurate bids from GC's.

Depending on the scope of work, you may be able to handle it yourself.

@David Bergmann can you tell us more about the scope of work required?

Personally "The Book On Estimating Rehab Costs" by J Scott was biggest help for me going into rehabs learning the scope of work, timeline, how to price out jobs, etc. 

I personally like to use sub contractors and oversee them so I can dictate the scope of work and timeline but thats just my style.

Sewer scoping.