I'm not sure it does take them into account twice? Some laws limit suffrage to only those of a certain minimum wealth, but I think everyone who meets that requirement has equal say. The number listed, I believe, is just to represent the share of clout vs. other sources. Someone asked the dev about a "one man one vote" system, but I think that was referring more towards the ideal of such a system rather then literally asking if there was a law that gave votes that were equal to each other.
In response, the dev showed us the most egalitarian law, anarchism, which has, as two separate effects, the establishment of a voting franchise that creates clout, and a penalty on clout from wealth sources.
I'm not sure what other sources of clout there will be aside from Wealth and Votes, but I think some events and laws can effect it.