Vote/Unvote a question many times and points sum up?

My question is regarding Easydiscuss points that are integrated into EasySocial.

I give 3 points for voting on a question, and also give 3 points (not deducting) for unvoting on a question (I need to promote that users would give real opinion weather it's positive or negative). I do not think it's good to force them vote only in a positive way as that would not reflect real situation, it's not fair to deduct points only for the reason that he thinks that question is bad for example as the main reason is to find out users opinion which questions are good which are bad. As it is allowed to change opinion about voting and unvoting many many times. So the problem occurs that user votes on a question, then unvotes, then votes again and he receives (3*3=9 points), and that not OK.

I think it would be much harder to ask how to deduct points for changing mind (voting on the same question), and it's maybe easier to ask how to make that user could vote on a question only ONE TIME. Is there possibility to edit any file to do that?