Playing multiple character on same account

According to SE "http://support.jp.square-enix.com/faqarticle.php?kid=67225&id=5382&la=1"--> you need REGISTRATION CODES to play multiple characters on the same account.

I have a main SE ID account but under mog station, it also has an option to add new service account. Does it mean that I have to buy a new game out of the box to get the code?....also if I do buy the game and get new code, will the new code be able to apply to the same service account that I have or do I have to add a new service account on mog station........ What I really want is to have me and my cousin be able to play 2 characters I have on my SE account on the same server.....but I am hesitating to buy another game copy to get the code and then each month I have to pay double to subcription for 2 game service.....which cost like 26 dollars a month.

According to the website from SE listed above...."You are able to play multiple characters." But are they talking about under same SE ID and same service account on mog station, and also do you have to pay extra subscription per month or is it that you pay only the standard fee of 12.99 per month but at the same time you are able to play 3 characters simultaneously on the SAME SERVER. The answer is not specific enough at all.......I hope they make it clear so for people who purchase the packages or code....they wont be using on the wrong account and calling SE to contact....SE has no call center for FFXIV ARR right now.........I hope some of you can give me a sure respond.

I play 8 characters of 4 worlds. I have lots of empty slots left for more new characters. I bought 6 characters in FFXIV-1 so part is carry over from that. I picked up 2 new characters in Beta. But I do not think they cost very much even if you have to pay for them later. I forget the details but Beta and Legacy players get a lot of free characters on a lot of worlds.

Right now I am not paying anything for them and when I registered my account for next month I did not get any additional fees.

You have only 1 SE ID and one Service account?.....are you able to play different characters on the same account simultaneous online at the same time? Yeah but each character will cost me 30 dollars to buy another window code to register.