Finally cracked how SuperGrok billing works.
Your weekly quota is fixed and shared across XAI, Build, and Chat. The difference comes down to multiplier rates and caching.
XAI burns way more credits per call than Build. Also if you're routing Build through 9router like I was, you get zero cache hits. Only the official Build CLI actually caches.
Someone tested it: the official Build CLI pulls at least 1B tokens per week on SuperGrok's grok-4.5. Build CLI went open source recently too, honestly pretty solid as a daily coding agent.