It does appear that Peter pointed out the correct info, and the $45 or $55 fees include the gratuity under the guise of 'service charge'.
For beer drinkers the $45 package is 8 bottles per day, which some have no problem downing. RCI charges $5.25 for their 16 ounce beers.
I think it says something when they say it is only offered on 7 night or longer cruises. People on shorter cruises tend to drink more so the company would not make money with the package. They want those cruisers dropping their SeaPass on the bar every time they order. People on longer cruises tend to drink less, so buying the package is in RCI's favor in those cases.