Team A's coach request a timeout to point out that the scoreboard has an incorrect score...By rule, is Team A charged a timeout even if coach is correct..since the scoreboard is not the offical score??

If the coach calls the time out to tell you, it has to be charged. Usually in this situation, the coach will get my attention and I will take my time to clear it up. I just make sure both coaches know what's going on and why I stopped the game. I've never had problems handling it this way.

By rule:
If the scorebook is correct, the team is charged with a timeout.

This should never be a problem because:
1. Any coach that knows the correctable error rule will know not to request a TO for the scoreboard.
2. Any coach who doesn't know the rule won't request the TO, he will just yell that the score is wrong!