I have read that excerpt that you attached. However, I still don't understand if that definition of principal place of business is based on just getting the home office deduction or if it applies to getting mileage as well. I do not claim any other expenses for this business except for mileage to photoshoots and equipment and other directly related photography items. We don't have a room that is exclusively used for editing photos and doing other administrative things as we dont need a separate exclusive room to perform these tasks. We just use our bedroom. So in this sense, I don't meet the exclusive test of principal place of business but does that mean I cannot claim miles for when I leave my house to go to photos? I have yet to find an answer to this question. I even looked at that flow chart on the excerpt you attached but that specifically says for the home office deduction.
