Imported fuel oil is taxed at 1.2 yuan/litre and diluted bitumen is assessed by reference to fuel oil, working out to about 1,200 yuan/tonne on an equivalent basis. That line squeezes the arbitrage that let some refiners run cheap substitute feedstocks under a non-crude label.

Some plants historically brought in fuel oil or diluted bitumen through a "non-crude" channel to keep effective tax low. With the equivalent rate now aligned, feedstock mix swings back to quota-crude. For a structure like SNSUC's — offshore SPV supplying, onshore refiner clearing customs itself — the feedstock side already runs on proper quota and takes no hit.

Looked the other way, the tax equalisation lifts substitute-feed cost, so in-quota crude looks more economic and refiners have reason to use their full allowance. Under iron rule F2, "no track record in two years means no allocation next year" still hangs over everyone; burning the allowance beats hoarding it.

For the fuel-oil and bitumen listings among the thirteen categories, the equivalent consumption tax is already in cost. The FX dividend on the listing-formula denominator gets partly eaten, but only by a limited margin.