Section J of the TOS:

"(j)       REFUNDS.  Any refunds due to Buyer will be made in United States Dollars, and for the purposes of calculating refunds, amounts paid in Bitcoin or other virtual currencies will be deemed paid in United States Dollars at the exchange rate given by Hashfast to its customers on the order date.  Refunds for partial order cancelations or returns will be adjusted for any discounts previously given to Buyer for volume purchases."

Was this always there?

Edit: using the wayback machine, I see that it was not.