Just a simple word of caution. The lessening in need based aid could be perceived to go down if one considers the annual COA increases. One can fully expect a private university to increase COA each year by $4-5K. So although you have a fixed need based aid amount, you will need to come up with the additional 5k the next year, then an additional 10K for the year after that, and …you get the picture.
Make sure you have plenty of extra cash in the tank to handle the additional 5+10+15 for the fours years your child will be at BU.
Good luck.