I m not sure about this argument The information that we have an Wikipedia so far says that there were other Vibhajyavada school not only Theravada For instance Schools of Buddhism says that the Dharmaguptakas were also Vibhajyavadins By English language tradition the default language for talking about Buddhism in general is Sanskrit or BHS Vibhajyavada and Vibhajjavada are roughly equal in Google hits with a small advantage for Vibhajyavada Charles Muller s Digital Dictionary of Buddhism also has it as Vibhajyavada Nevertheless I m going to leave the article where it is for the time being