Msc Fantasia debarkation

I was wondering what is the latest time to debark in Barcelona. We will only have hand luggage so would we be able to get off anytime or do we have to get off when the colour for our deck is getting off. My understanding is the colour you are assigned is really only so that your luggage will be waiting at the terminal collection area when you get off, but as we don't have luggage do we have to get off at that time regardless? And also, what do they do if you do get off later than your assigned time?I don't mean hours later but say your assigned time is 9.45 and you don't get off until 11.30.Could they charge you for being on the ship a little longer than expected?