Absolutely. I was in a chemical manufacturing business and we did exactly that so that we could meet demand while incurring downtime for maintenance, construction, and upgrades. To us, it was a matter of keeping our customers happy. In California, gasoline producers don't need to worry about that, because of boutique formulations called for by the complicit thugs in the Air Resources Board, chief of whom was a lawyer for the Natural Resources Defense Council. Yeah, them again, those greenie thugs working for major petrochemical energy investors. You don't want to get it.
An example is that we pay nearly twice the price for gasoline on a cost per mile basis as they do in Texas. I know this from personal experience: We took a cross-country vacation in 2010. We were paying $2.65 for an 86 octane formulation and traveling at 65-70mph in a Chrysler minivan. When we got to Texas we were paying far less than $2 for an 82 octane formulation, and getting 25-27 mpg at 80 mph.
The producers couldn't get away with that without a closed market. That's why the NRDC is their best friend.
Did all of your competition produce the exact same product, same specification? The only difference in gasoline brands is the additives added at the loading rack.
Refining margins are very tight. The don't allow to spend hundreds of millions of dollars per major unit to duplicate capacity and not use it.