Company Z processes 4 different products that can be sold without adding additional labor or cost, or can carry out another process and then sell it. The data for both circumstances are as follows:

product	Sales price without adding additional labor	additional labor cost	Sales price after adding additional labor
x-1	$2,000	$800	$2,800
x-2	$800	$725	$1,000
x-3	$1,800	$650	$2,900
x-4	$750	$210	$950

Determine which product(s) should not or should be added additional labor or cost and then sold? Explain your answer and present the calculations that justify your answer.