If the Fairbanks store doesnt offer the discount I suggest a visit to the Anchorage branch. Generally speaking a 50% deposit is required and both tents being ordered should be the same but they "may" make an exception to the rules depending on if you are a repeat customer or not. The orders must be done at the same time on the same invoice.
Myself and another forum member just completed our deal yesterday and the orders were written up on the same invoice. He paid for his and I placed a deposit on mine as it was ordered with extra gear pockets and a different size stove jack.
The folks at the Anchorage store bent over backwards to help us. I asked that they put an Artika tent on display so I could decide what options I wanted to add and when I showed up they had it ready and they had the 10x10 up as well.
If anyone is serious about combining orders with a friend to obtain the 10% discount I have a couple of suggestions for you:
1. Make sure your friend is committed and will not leave you hanging.
2. Call up the manager (very nice lady in Anchorage but her name escapes me) and tell her your plans and make an appointment to place the orders.
3. Be prepared to pay at least 50% down when you place the order. Sometimes they have the tents in stock so they will expect you to do a cash and carry.
4. See suggestion #1 again.

Your experience may vary but this is the second tent I puchased with a friend to receive the 10% discount. Good luck in your purchase