There's so many factors that play a role: whether a company will restock a sold out album or not, whether there's a re-release, whether charts will include that re-release or not, how the promotion is done or not, and even how the title tracks are received. TVXQ had their own rereleases.
In the end, the results were that SNSD and KARA had albums that outsold TVXQ's best selling albums, that TVXQ or other groups never caught up to, and did SNSD have an album that was the best selling Korean album of that year.
If you want to exclude those albums, that's ok. Like I said, I disagree with the reason behind it, to me those count as much as other albums, but agree to disagree.
