Also assumptions on cost if you pick and they buy A $10 a square foot flooring when they budgeted $5, big difference.

You could also call a couple of contractors on the phone and get rough sqft pricing from them for roofing, siding,  painting etc. like how much the averages costs are per square (100 square feet) and square foot .

OpenAI, a leader in artificial intelligence, has leased the entire 315,000-square-foot building at 550 Terry A Francois Blvd. in San Francisco’s Mission Bay neighborhood.

In 2020, I built under $200 a foot with long-term rates in the 3's to get 40% ROI.

Not trying to sway anyone either way.Also not sure about the specific transaction you are talking about, but if you saw it on YouTube it is likely just a marketing move to drive attention and traffic to his work (which seems to have worked here!). 

@Dalton Foote I think this is the key point. 

I had been insuring at $350-$400 a square foot value the last year or two

Does it have 36" windows egress, 7 foot ceilings, egress doors, HVAC, and closet door? 

Hope I haven't shot myself in the foot by giving out the location but I'm thinking you all have bigger fish to fry anyway, lol! 

The 315,000-square-foot space in Mission Bay adds to OpenAI’s nearly 1 million square feet of leased space across the city, including properties subleased from Uber last year.As one of the largest AI firms in the world, OpenAI’s expansion is helping revitalize San Francisco’s struggling office market.