Additionally, how many calls does it typically take you to successfully close a deal using this approach?

That's typically because they have a lot of money and experience.

I think they typically give 20% off the annual subscription. 

Its my understanding through my reading/research that 35% is the typical number.

If this is the case then typically you only have to comply when you make alterations.2.

These platforms typically have billing policies where you pay a per unit fee per month to the software and you get regular updates and support each month.There are a number of low-cost platforms available that are able to offer you a lower price by passing along some of the costs to your tenants (payment processing fees, applications, tenant screening, etc).

I know DSCR lenders typically don't touch them.

Both these 2 are not easy to do, and typically take expertise, experience and or capital.  

What you will find is they typically appraise for far less than the hands off cost to add the ADU.  

Investors typically want to stay within the original budget.The only way to do this is to stick to the plan and avoid COs!