I liked your previous 2 posts and you are making some great points. But this post you just got it all wrong. You are not getting SP based on the dollar amount on posts. The dollar value is calculated based on the SP you are about to receive.
Your entire argument is just plain wrong. If I make a rough estimate If you have 10,000SP and vote someone 100% while your voting power is 100% you are giving that person 1SP. The dollar value shown on the post is based on the witness price feed of STEEM. This is why the value of your vote fluctuate when STEEM price go up/down.