Here is why you don't wait 11 yrs to re stain your deck. They let time get away from them before calling me out to clean re stain their deck. It was pressure washed then used a light 12 % mix then rinsed no brightener was used.
It was 2 parts 12% 3 parts water and some soap it's the same mix I usually make for most decks I clean. I don't think you need any more 12 % than that to clean wood.
The deck to a whole 2-3 gallons of stain and 2 hrs to stain.
Yeah I think so since the cleaning cost are more when I have to clean the deck this much. I didn't strip it but pretty close so I adjust my pricing depending on how I have to clean it.