That's awesome!! I hope you are feeling really proud of yourself! I hesitate to suggest anything since I have quite a ways yet to go, but if the Spark program helped you set up a calorie counting and burning program that worked so well, I'd set a maintenance goal and continue with what it suggests. That's what I plan to do when I ever get to my goal, anyway!
You've got to the top of the mountain, so you perch proudly up there and enjoy the view!!