That is correct, in addition I have contracts with companies for support as well as development of open source features. The hosted API is "free" in the sense

That is correct, in addition I have contracts with companies for support as well as development of open source features. The hosted API is "free" in the sense that there are no tiers. The API costs me money to run, which is why I require a GitHub sponsorship for commercial use. This is ideal for use cases where deploying your own tileset is impractical. If you are using the hosted API heavily then it makes sense for you to "graduate" to deploying it yourself.