I am cooking two identical 2 pound pieces of beef. It calls for 25 minutes per pound. Do I figure the cooking time for 2 or for 4 pounds? The cooking time for 2 pounds would be 50 minutes and for 4 pounds it would be 1 hr and 40 minutes.
If they are generally the same shape and size, be sure there is room between them for air to circulate and base your initial cook time on one piece. Of course, time is not a very accurate measure when roasting in an oven. So, your best bet is to use a thermometer to achieve your desired level of doneness.