原话： 
On the Pro 5× plan, access is structured differently across model tiers. GPT-5.4 Thinking Heavy (and lower tiers) are available with effectively unlimited usage, subject to standard abuse guardrails, similar to how “unlimited” access has been described previously. 
However, GPT-5.4 Pro on the Pro 5× plan does have a limited (unpublished) usage allowance. While this limit is not typically rest...