You should only have to change when your current software has a flaw or lacking feature that is causing you to spend too much work on a work-around.

It’s inspiring to hear how creative finance has changed the way you approach deals.

But when you focus on EFFECTIVE purchase capital requirement, notice how that 1 little change of wording totally shifts mindset, focus, everything. 

Therefore it's quite normal for a design change to be an additional service fee. 

However that means you have to move it or change the box code if you don't want them to keep accessing it.

There is no differential factor number, however, it will change if you are buying tenant occupied, if they are are going to be vacant at closing, if they are going to stay the full lease or you have to pay cash for keys.

If something happens to affect the cost you might be able to change the scope of work or timeline to compensate for that.   

We can remotely control the temperature, but if someone (a guest) manually changes the thermostat, it overrides our remote settings, which is what we want.   

the 500k tax treatment will always be there.. ( unless code changes) .

I don’t think a three year historical lookback is sufficient.Unless the market fundamentally changed, I would just sit tight.