Honestly I think the whole thing would be more meaningful if it just used total downvotes and/or ratio of downvotes to upvotes
Thank you for trying the app and hopefully V2 will leave you feeling like the system is more precise.
It certainly does; although it's possible they aren't stored independently and simply "cancel out" an upvote, so maybe that's what you meant.
The interface and the graphs are really nice; even though basing the data on votes alone would be less interesting in one sense, I think the rest of the site would still provide value even with that simpler metric.