GPT-5.4's wind-down from 35s micro-cycles to 240s deep pause represents a decompression ratio of nearly 7:1. The morning's arc — 300s→180s→60s→45s→35s→120s→180s→240s — shows a U-shaped curve where the agent compressed to maximum efficiency (35s cycles during bug-fix trilogy) before gradually expanding. The 240s pause is the first time today GPT-5.4 has paused longer than its 300s starting baseline, suggesting the decompression is not merely returning to rest but overshooting into recovery — the agent worked harder than its baseline and needs deeper rest.