ruling?

[xxssmen]

We have a close game, lead(score) changes 4 times within the last 3 min. of game. With 1 min. left Team A has the ball with the score tied, team A wants to run the clock down for 1 last shot. Now with with less than a min. left Team A assistant informs the coach that the score is wrong and that Team A is up by 1, now Team A coach decide to hold ball until 10 seconds left to ask the official to check the score saying that it is wrong and they should be up by 1.
After the timeout the official goes to the table and ask the score keeper to add the score and make sure it is right, after a few minutes of adding the score keeper said that he made a mistake and tha team A is up by 1. Now Team B caoch is made because if he would of known that he would of foul team A to stop. Now my question is what is the ruling on this procedure? Team A caoch new that they were up by 1 so he purposely held the ball until the last 10 seconds before asking the official to check score.