Yes. With a standard multi-domain certificate, you need to list the subdomain as a separate SAN to cover each one under the multi-domain certificate. Please note that, unlike a wildcard that secures unlimited subdomains, a multi-domain SSL certificate by default secures 3 to 5 different SANs only. In order to add more SANs, you must pay additional charges after reaching its maximum coverage capacity. Another option is to opt for a multi-domain wildcard certificate, which will secure unlimited subdomains on each domain you choose.