I picked up some 10w30 Valvoline daily protection on clearance recently that is GF-6A, SP rated. 5w20 and 5w30 Valvoline daily protection are advertised as synthetic blends while 10w30 makes no such claim. I checked the Valvoline website and it dosen't say 10w30 is a blend either. My question is since the 10w30 meets the latest GF-6A SP rating is it possible to still be a conventional oil?