Since RA is an option, you are not penalized for not having it offered and you shouldn`t substract 0.08% from your BS calculation. What you should do is add 0.08% when the option is offered.Big difference.
As an example, if you look at most BS tables for 6 decks Da2 and S17, you will get -0.54% as your starting disadvantage. If the RA option is given to you, you will add 0.08% and have a starting disadvantage of -0.46%. The fact that the option is not offered, won`t put you to
-0.62% over the top.