Especially when there are already leases out there that are attorney-approved and widely in use. 

They sit on a 6 acre property and it has a 6 ft high 80 ft wide waterfall in the backyard.

This helps for building wide announcements etc.

I know 3 that write them locally in DFW...and only one of those will do it state wide.

Here is an article I wrote in this widely misunderstood topic:  https://www.wellingscapital.co...Good luck! 

You'll find a wide range of experts and experience levels.

Any nation wide companies you recommend or is it best to find the top notch ones locally? 

I sell STRs on the Emerald Coast, and you can get a lot of rental data from awning.com's Airbnb Estimator if that's your direction.Insurance is going to vary widely, depending on where you are looking. 

So can somebody please explain why we use the first formula (above) instead of the widely acceptable second formula?

Prices will vary widely and you need to know why that is.