Contained DB best practices

Hello!

A standard procedure for converting an ordinary db to the contained one is as follows:

http://msdn.microsoft.com/en-us/library/ff929275.aspx

sp_migrate_user_to_contained 
@username = N'Barry',@rename = N'keep_name',
@disablelogin = N'do_not_disable_login' ;
On the other hand, this article says:
http://msdn.microsoft.com/en-us/library/ff929055.aspx

"As a best practice, do not create contained database users with passwords 
who have the same name as SQL Server logins."- 
But the commands mentioned at the begining of this post do create 
"contained database users with passwords who have the same name as SQL Server logins."
Does it mean we must NOT use @rename = N'keep_name' (or @disablelogin = N'do_not_disable_login') 
to follow best practices for contained DBs?
Thank you in advance,
Michael