The deferred revenue aspect is an interesting accounting problem. What changes allow recognizing that money? Are those only from new "features" and not from "improvements?" E.g., Smart Summon is only allowed within ~200 feet right now, but if that restriction is removed, there's no additional revenue from existing owners?
At least from Zachary Kirkhorn from Q3 call: "Note that with the release of Smart Summon in the US, we were able to recognize $30 million of deferred revenue. As we expand Smart Summon to additional markets and release new features, we will continue to recognize additional deferred revenue."
So if we follow what the CFO said explicitly, it seems like revenue recognition comes from "features" that have been made available to owners in a given region.
If Tesla really needed a revenue boost for Q4 and "feature complete" isn't ready, would they release a partial feature, say only stopping at traffic lights but not resuming nor stop signs?
Maybe Elon Musk has always been talking about "feature complete" from an accounting perspective instead of an engineering one…