The same thing has happened with me. My hubscore was 94 but now it is 92 and my hubkarma has raised to 97.
Hubkarma depends on the number of links you post in your hubs. And if you have a lot of them you surely will have an amazing hubkarma score.
Author score depends on the number of hubs you publish, their frequency, originality and the number of people viewing your hubs. And if your author score is going doing its time to publish something new and original again. Good luck hubbing.