Gail decides to buy a Treasury note futures contract for delivery of $100,000 face amount in March, at a price of 1305.5. At the same time, Robert decides to sell a Treasury note futures contract if he can get a price of 1305.5 or higher. The exchange, in turn, agrees to sell one Treasury note contract to Gail at 1305.5 and to buy one contract from Robert at 1305.5. The price of the Treasury note increases to 13015.0. Calculate Robert's balance on margin account. Assume that initial margin is $1,890.

My professor got (1,593.13) as the right answer, but I got something else