Since you are using 2 items you must add them together and divide by 2 to get the average.
(45+60)/2 = 105/2 = 52.5 SO (.12 + .09)/2 = .105 ... so the answer is NO it is not 1 oz! 1 oz is going to give you 1 PPM if the chlorine was 52.5 %
Try again!!! Now to add to your misery, each teaspoon is 0.16 oz so you need to know how much chlorine does a teaspoon give you. 8-)
**Just kidding** ... I did the calculations a while ago and you need 0.096 oz of 56% dichlor to give you 1 PPM chlorine.
To make it even easier for you, I have a 400 gallon tub and I use 2 heaping teaspoons to get about 3 PPM +/- something. The only difference I use chlorine from Doc that has 62% active ingredients and the amount needed to get 1 PPM is 0.087 oz.