Subaru Repair: scheduled maintenance, brake fluid flush, driving condition

Question
I have a 04 Impreza Sedan and love it!!  I plan on keeping it.  The mileage is presently 45K.  I contacted the dealer about scheduled maintenance, they say I need to change the Auto. Trans. fluid every 30K, I contacted another Sub. dealer, they say our state (VA) qualifies as a "severe driving condition" and stated it needed to be changed every 15K. Over 90% of my mileage is cruising at 55 mph or interstate driving.  I have no problem if my car needs this, but I would rather not spend money on something that's not needed.  They also stated I needed to flush the grease out the front and rear differential every 30K.  Is this something that is legit?  Thanks for your time and help.  (I was planning on changing the fluid at 60K).

Answer
Our services recommend, tune up, transmission and differential drain and fill, coolant flush, brake fluid flush every 30k. air filter, and battery/alt test every 15k, clean and lubricate brake pads and calipers every 7.5k, oil change every 3k. I hope this helps