This is an interesting double edged sword.
Side one - check in your owner's manual to see what Ford (the manufacturer) suggests for each major service. You may have to choose between regular or severe service schedules. Some people swear by this.
Side two - the dealer has it's own idea of what needs to be done at what interval based on a lot of factors (climate, location, type of vehicle, condition of vehicle, what they've been selling to all the other vehicle owners, what the owner of the store thinks, etc. etc.). If you've been going to the dealer religiously and following their maintenance schedule (which is usually WAY different than the manufacturer suggests) then keep on their schedule. You'll get a better response both to your face and behind your back that way.
If you're upfront with them about what you want done and why your changing your mind (if you are) and stick to this changed schedule in the future, it should be cool. If you waffle back and forth, you'll get another reputation at the store that won't be good.
I worked at a high-end luxury dealer as a service tech for 5 years and that was the "policy" - follow our maintenance schedule which is tailored to our state (weather, road conditions, etc.) with a generous helping of what the manufacturer suggests OR follow the one in the book religiously (you pay less at some major services, more at others no matter which way you go, but it's all a wash). Don't nickle and dime and try to go al a carte from both.
Wow, that was a long answer
Hope it helps
2007 Mustang V6 regular maintenance questions. 
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