So its a benefit to the seller to be able to counter the  commission right on the counter offer form so its there in black and white..

This would be ideal in terms of cash flow (after a few years) and equity appreciation since you'd be achieving tremendous returns on limited equity in the form of appreciation, principal paydown and tax benefits aside from only cash flow. 

These include the actual cash flow (NOI), Your net cash coming in after expenses and allowancesDepreciation - the tax benefit that lowers your taxes. 

Land doesn’t depreciate, and while buildings require maintenance, they usually gain value as markets grow, demand increases, and inflation takes its toll.Real estate investors benefit from a significant tax write-off based on the concept that properties lose value over time, even as their market value skyrockets.

- Is there a cost/ROI benefit of a 2 floor ADU plan vs single floor vs Loft ADU floor plan?

The appraised value seems low and I am trying to understand the best strategy to challenge this value and the cost / benefit of going through the condemnation process. 

It will familiarize you with the basic terminology and benefits.

@Allan Smith We've seen SFH properties with a purchase price as low as $150,000 benefit from a cost segregation study.

I will say however, that there may be an indirect benefit to not APPEARING to hold many valuable assets.  

Quote from @Melanie Baldridge: Did you know that Limited partners or real estate investors can absolutely benefit from depreciation?