In the past, links from subdomains (ie: example.seo.com) were classified as external links. Even a link from the non www version of your site was classified as external. With the changes, links from these types of domains will now be considered internal links, as long as you also own the root domain.
With this change you may notice your total number of external links go down, but this is only because some of your links that were previously classified as external are now being classified as internal. Your total number of links should remain the same.