Cushman Electronics reported a net loss of $2 million in fiscal 1987, which included an extraordinary credit of $142,000 from halting the company's retirement plan. That is contrasted with a $642,000 net loss for 1986. Sales for the year ended Sept. 30 declined 11%, from $7.7 million to $6.9 million. For the fourth quarter, the Newport Beach company lost $1.5 million, including a $951,000 loss on discontinued product lines. In the fourth quarter of the year before, the company reported a net loss of $295,000. Net sales for the fourth quarter were $1,152,000, 40% below the same period in fiscal 1986. As a result of the 1987 net loss, there is a shareholders' deficit of $141,000 as of Sept. 30, contrasted with shareholders' equity of $1.9 million for the same period last year, the company said. Cushman Electronics, which has its headquarters in Newport Beach, sells and services telephone communications systems products.