No. When we say you can cover "unlimited subdomains," we truly mean "unlimited subdomains." No tricks. No hidden charges.    However, all wildcard certificates would include only the first level (rather the next level of the primary domain) of subdomains. So, for example, if you have listed *.mysite.com as the primary domain, it will cover billing.mysite.com (first level subdomain) but not refunds.billing.mysite.com (second-level subdomain).