That's your difference. Not saying this is always true but you're typically gonna have a higher quality install and someone that puts more effort into each job with a one man show. Similar scenario you take your vehicle into the dealership to have work done cause who knows your vehicle better than the dealership right? Wrong. Truth is they've got some kids in the back they may have two years of experience, and you're going to overpay. Why, cause they have a fancy waiting area with cheap coffee and stale chips. Now the mechanic right down the road who's been doing his job since the 80's and hasn't updated it since then can probably tell you before you walk in what's wrong with the vehicle.
Your one man show has a lot more to gain or lose with every customer. The big name places well honestly they couldn't care less and are just going to say you're being to difficult to deal with. Which yeah you're being picky but not completely out of line.