I own my STR in a single member LLC. Can I use the Augusta rule?

I watched the video on cost segregation and have a question why the % changes depending on what kind of study you would be doing. Can anyone explain and how do I calculate what would make most sense for my tax situation?

I’m setting up a LLC for my property which will be owned by a holding LLC. My attorney says I need a management LLC as well and shouldn’t use the property LLC for my business (STR income and expenses). It seems like a lot to set up for only owning one property. Any thoughts?