Can I use letsencrypt in more than one subdomain?

[MakarkinPRO]

http://screencast.com/t/5eFfauHLKU2 - just run a command following that instruction http://doc.ispsystem.com/index.php/Integraion_with_Let’s_Encrypt is look http://screencast.com/t/gDNPC8Q7Xa here https://crt.sh (I didn’t see that any new cert been created).