I'm happy that we agree on this. Having said that, I would note that your example, while certainly valid, is IMHO of a too small scale (literally and figuratively - the latter with regard to complexity) to comprehensively illustrate the "mental models" concept. When I think about mental models, I'm thinking more about analysis frameworks typically applied to much larger and usually much more complex systems than technical ones, mostly sociotechnical and socioeconomic systems (e.g., open source ecosystem, startup ecosystem, innovation, science, corporations, stock market, finance, economy, policies, politics, society, history).