Gasoline, coming from raw materials in turbulent countries, is unfortunately a very volatile commodity. Furthermore, demand is completely inelastic, as humans need a lot of it, it spoils/goes bad and most don't have the means to store it as it requires special handling to transport and store. The buying public is different too; gasoline is bought by consumers and businesses. But generally most buyers buy at the retail level (due to government regulation) and do not negotiate much on the price.
Paint on the other hand, there is some elasticity in demand. If paint prices shoot up, consumer demand is somewhat elastic. Business demand for paint may be less elastic, but since business buyers are so large they can negotiate.
Trust me, if Mercedes Benz raised the price of paint twice in a six week period, I'd be ticked too.