Yes, MSC puts the $12 ppd on your account, this is because the tips go to more than room steward, waiter and assistant waiter. It also goes to the Head Waiter, Maitre D' etc.
Also when you order something from the bars the tip is included in the price so no extra 15 or 18 % added.
You can have the auto tips removed but you do need to do this early in the cruise.
There were many on our cruise that had the auto tips removed as soon as they boarded. We left ours in place. But did not add any more.
Star Princess 2005, Sun Princess 2005
Caribbean Princess 2006, MSC Lirica 2006 , NCL Pearl 2007, Majesty of the Seas 2008, Carnival Destiny 2008, MSC Lirica 2009, Carnival Valor 2009,Carnival Legend 2010, Carnival Liberty 2010,Carnival Fantsay 2011,Carnival Valor Feb 2012, MSC Poesia Dec 2012, MSC Poesia April 2013, Carnival Legend Nov 2013, MSC DIVINA Jan 2014