Incorrect.
A vote reduces your VotePower by 2% if you have 100% Votepower and are voting at 100% voteweight.
So if you are upvoting with 100% VoteWeight and 50% VotePower, you would lose only 1%... So it's: 2VoteWeightVotePower
That would make a 10% Vote at 100% VotePower lose you: 20.11 = 0.2% VotePower lost.
I hope that this clarifies it... If you still don't understand it, please reply.