In regards to your question about prior charges "going away" after purchase of a drink package. I just had an experience with that situation a few weeks ago on the Emerald.
I purchased the package immediately upon boarding (at least I thought I had), the crew member scanned my medallion, called me by name, said thank you, and off I went to the closest bar. Later in the day I noticed several bar charged on my folio, I went straight to customer service and was told that I had not purchased the package and they had no history of me attempting to purchase the package. Customer service put the package charge through, but advised that they could not remove bar charges accrued prior to purchase of package. I asked to speak to a manager, the manager removed the charges, after explaining the policy again. However, they would not remove the Boston City Tax that is applied to drinks purchased while in port. So...be prepared to protest if you purchase the package on the 2nd day, and prior drink purchases are not removed.