Opinions on Wolf's Head oil

[Largecarz]

I just changed out Wolfs Head extreme duty 15w40 in my Detroit Diesel non egr 500 hp 12.7 litre engine.I change @ the detroit recomended 15000 mile interval,and the engine holds 40 quarts.My observations in a real world enviornment are the oil is ok.Using Rottela conventional 15w40 i use 2 gallons of oil in between changes.Using the wolfs head semi syn,i used 6 gallons of oil,same duty,same enviornment.The wolf from my local vendor cost 11.50 per gallon.Rotella @ walmart is 13.40.Back to tried and true Rotella for me.The Wolfs Head was fine,just not as fine as Rotella.Just my opinion.