I have ran the numbers pretty conservatively to ensure I don't get blindsided and just want to ensure that the increase wouldn't make the deal a no-go from a financial standpoint.This would be the largest building in my portfolio thus far and just don't want to let undue fear hold me back from taking advantage of a good opportunity. 

No, the homeowner is always blind sided with cost over runs.

I can't personally see any large event coming that would tip it, but then again, as a late 20-something with a millwork business in 2008, I got completely blindsided by the last crash (idiocy of youth, I suppose) and spent the next 3 years trying to just survive.  

I'm feeling really blindsided by this.

If your buyer was working with an agent prior to contacting you, the agent should have negotiated for them.I'm an agent, but I can understand why you would feel blindsided by this sudden appearance of an agent.

@Bob Barilla This is the one aspect of the BRRRR strategy that is not talked about enough and until you go through it the whole situation blindsides you at first because you trust your numbers going into the deal.

If you take into account what you're including - I would say that's a far more accurate number thats actually including deductions which may be a blindside to new investors.

It is just that I can (and did) easily drive by it and I can't be silent and let someone get blindsided just because they can't drive by it as easily.

These retrofit projects will be BIG.I wanted to bring this up to the Biggerpockets community because I want us all to succeed and not be blindsided when these requirements affect our livelihoods.

I will do that so I'm not blindsided by my ignorance.