Diglyceride acyltransferase that uses fatty acyl-CoA as substrate. Particularly active with oleate as a substrate. Has no wax synthase activity to produce wax esters. (9Z)-octadecenoyl-CoA + 1,2-di-(9Z-octadecenoyl)-sn-glycerol = 1,2,3-tri-(9Z-octadecenoyl)-glycerol + CoA Belongs to the diacylglycerol acyltransferase family.