Im not 100% , but my understanding is that voting power does not deplete linearly (though if the depletion is linear, you're correct). I think thats what the chart on page 19 of the white paper is about.
To stick with the fuel analogy, its like a car that burns more gas when the tank is more than half empty. You lose out if if you let your power get too low. I think.
I know - the whitepaper is very weird and misleading on that point. I had to reverse-engineer the algorithm myself from the code before I actually believed this, since it's not documented anywhere. Each time you vote, that gallon of gas you take out of the tank all goes completely to upvoting the post; none of it gets wasted on something else. Your car is just as efficient with an empty tank as with a full tank, it's just slower (might as well beat this analogy to death). It's exactly this:
power_after_vote = power_before_vote - used_powerwhere
used_powergets multiplied by slider power and SP to calculate thersharesthat go to the post.That exact expression shows up in this line of code.
OK, i see what that graph is saying now. Wow... ive actually bee spacing them all this time.
Incidentally, based on this, I made a model... tell me if you think I'm on point in my analysis.
https://steemit.com/steem-help/@sigmajin/the-tale-of-the-5-brothers-a-voting-power-parable