I have a 2000 Ford Focus SE with a 2 liter, four cylinder engine and automatic transmission. I just had the oil changed at the local quick stop service center, and while there was advised that it is past time that I have both the transmission and power steering fluids changed. Levels were OK (no leaks), and the car has 150,000 miles on it. Is this maintenance really necessary? Quoted prices were $99.95 for the transmission fluid flush/change, and $59. for the power steering fluid changeout.