Here is my suggestion. There is no real advantage (or at least hasn't been) for booking a package at Universal. My suggestion is contact LOWES directly and then also look out on Hotels.com etc.
I would book the room seperate and then get tickets from a discount place like Undercover tourist.
One of the things you will notice with the US hotels is that the price goes down the longer you stay. So 2 nights may be $250 / night, 3 nights $240 / night, 4 nights $220 / night. So that will factor into your price. Also be flexible with your dates. Last time we went - we wanted US at the end of the trip - however it was significantly cheaper for it to be at the beginning of the trip. We saved several hundred dollars by moving our dates just a bit.