Downhole formulations can include soaps, light fuels, and highly aromatic compounds such as xylene. What you are really doing is targeting single problems with certain chemicals, when one needs to treat multiple issues such as wax, alsphaltines, rust, etc. Xylene might work well (although it is somewhat expensive), but it might only target a single issue, and could create chemical reactions and cause additional problems. Petrozone (I'm guessing here)is highly aromatic and because it contains multiple compounds and can work in a variety of ways and on multiple down hole problems. Working both nearbore and out into the larger formation, you can clear more pathways and also increase oil viscosity to allow oil to flow to the well bore. There is a lot of blending work in the oil fields, and specific fields might require different blends of hydrocarbons, acids, etc. I'm assumeing Petrozone is also a blendable product, where it may hold into solution specific additives for specific applications.
No, but I stayed in a Holiday Inn last night !!!