No, because they were explaining why it's exactly not the way you're explaining..
You will have 98% voting power right after casting that 100% upvote, but, your next 100% upvote will not give out a full "100%" upvote as you are not at 100% voting power anymore, meaning it will also not burn a full 2% voting power.
being at 80% voting power,
your 100% upvote will only allocate 80% of rshares from the rewardpool as you can't upvote more than 100%.This means that your 100% upvote is basically only a 80% upvote and will only burn 4/5th of 2% voting power.
You are right that the upvote will only be an 80% upvote. But people do think with their slider and in my opinion it made more sense to write down the next 100% upvote. But I can life with your explanation :)
Cheers,
Peter