Yes, but you were saying it can be on a wall 4-12" down from the ceiling -- we were assuming you meant the low side of a vaulted ceiling. It would have to be up at the high point. That is what I thought what we were discussing. Certainly if 4-12" is within the 36" from the peak that is not an issue-- I thought we stated that earlier.
In certain areas that I work in the building inspector will require a installation guide to be present on the job site.The Firex brand normally has a good veiw of various conditions to help aid in the placement of their product.I found a piece of information(sourced from this site) that I'm no longer able to retrive at this time that really helped me concerning height and placement of the SD's.Often times the sq.ftg. and the shape and design of a room could require more than one SD to be installed.I have worked closely with several Firemen in this area.The pattern that the smoke takes will most likely be a curl pattern .So, it's very crucial to measure the 12''/36'' mentioned areas to insure that the smoke will pass across the sensor..
