Originally Posted By: stchman
Originally Posted By: Justin251
Maybe because the 20s required more synthetic than the synthetic blend?
And that might be true, but I would figure that it would cost more.
And possibly it does cost Castrol slightly more, but manufacturers typically don't vary pricing by grade, if it's within the same product line.
T-shirts in size "L" typically cost more to make than in size "M" because more fabric is needed, but they are both priced the same. The manufacturer figures out the desired margin by considering the cost to make all grades/sizes while having the same price on all of them.