While I was interested, (not for a profit, however) my instincts told me to be careful and not rush into things as my reputation was at stake if his data or service was questionable. 

Just to give everyone an idea of the scope of work needed, it includes new siding, roof, plumbing, extensive electrical work, full gut bathroom and kitchen, possible mold issues, and a few other smaller issues.

It's a complete gut job and we'll have to replace 15 windows.

Total gut on this bathroom, but look at these wooden floors!

Nor am I a pro at estimating repair costs, obviously.Obviously from the pics its a full gut job, new everything.

Trust your instincts because it is often better to make some concessions and get the deal done.

They planned on gutting the entire place which is why the renovation estimate is so high.I ended up negotiating the seller down to $280k which made the room for my fee.

Some of the flippers can probably give better numbers, but we are just finishing a complete gut of an old (120 years) small multi (2000 sq ft) which has been a little more costly to us than usual (gotta love ballon framing) and we are running about $20 - $22/sq ft ... but this is Canada and things tend to cost more here.From the advert you posted, it appears some of the demo remains to be completed and then you have an envelope to insulate and 6-12 complete units to frame, plumb, wire, ventilate, etc ... not to mention bringing everything up to current fire code.

My agent estimates ARV at $240k but doesn't have any good comparables so she's using her gut to tell her the value of the house.

House has to pretty much be gutted down to the studs and rebuilt.