1. Re Calcuating the upvote is taking out the previous vote and adding a new vote. These are 2 operations. Should it be atomic? Is it a transaction if one fails.
2. If its not atomic what happens in the curation limits? Lets say 24 hours exactly. Taking out the before 24h will affect more than adding the latter.

I am not saying its not a good idea, but as we saw with curation until today, any complexity is usually taken advantage by bots and keeping it simple (as much as can be in this phase with all the must complexity) seems like the way to go.