Is it the age of the house. the condition of plumbing/electrical?

What condition is the electrical in?

Just another angle if you haven't already done so.As a Electrical contractor (and some GC work) over the years I have gotten to the point of becoming extremely detailed in the work I do, doing so leaves very little margin for misunderstanding of work to be done and not to be done.Wish the best of luck with your situation.

If the utilities are on then that'd be a good time to check and make sure the plumbing and electrical convey.

All new plumbing, HVAC, electrical, garage floor, basement has been gutted and completely waterproofed.

I've done the 1st three units and the cost was really high between the costs of the units themselves, the plumbing electrical, HVAC/venting, and the closet build-out to house them.

The electrical was upgraded in recent years as well.

The Air conditioning wasn't turned on before she came in and it was too hot (tried saving electricity no one in home). 

Also take a look at utility costs - if you can separate them out and have tenants pay their own, it's helpful, because they treat the heat and electric use very differently if they are on the hook.  

I think the last one we did on a new build (2012) was >$1500 with the tank plus the ancillary costs of plumbing & electrical hookups.