On whatever market it is sold, WTI or Brent, the price of tar sand oil is discounted to compensate for the extra costs of refining. That does not make it cheaper because the lower price equals the added cost of processing. So why are you confusing the issue with this? Are you confused by it? As for added supply putting downward pressure on price. Mid-American refineries already have over supply of Canadian tar sand pipeline. Will the added supply to the international market affect its prices? Probably, yes, but we could spend a few years talking about that and still not understand it.