That is correct. it will work.
What I'm trying to tell you is that when you create multiple services (by adding +) then any cli changes to this group of services all ports will be affected.
lets assume I create multiple services (TCP/80 TCP/443 UDP/53) and now I want to change the session-ttl only for the TCP/80 port, I can't do that in the custom multiple service that I created. Because any CLI changes will affect all other ports on the same multiple service you craeted.