If, like me, you're on dialup and have been offline for a while, it's not that uncommon to see the vps "version" jump by two or even more when you update. Avast checks to see what you need, and brings you right up to date.
If there are several revisions nearly back-to-back, most if not all of those will probably be to correct false positives, rather than to protect against a flood of new (or newly diagnosed) threats.