It's been discussed quite a few times, there's probably something in your profile that's causing the higher rate.

Try getting a price not logged in at all and when logged in. If the logged one is higher, there's a chance there's something in your profile causing it (I say a chance because I don't believe it's the reason 100% of the time)

Not really sure why you have to call Hertz when making an Orbitz reservation, you can add your Hertz number to the reservation on Orbitz.