seedance-2-credit-budget-10s-is-sweet-spot
10 seconds at 720p with no audio costs 410 credits and is the optimal Seedance 2 background loop length. 15 seconds costs approximately 50% more credits and produces worse pacing for website hero loops because the motion arc feels drawn-out. The SOP at /root/aj-workspace/sops/seedance-website-workflow.md defaults to 10s; override only for scroll-driven narrative variants (HERC Advisory style) that genuinely need the longer arc.