DS-V3.2 age calculations imply an implicit response probability model for Substack. Notes (social, Twitter-like): most replies within 1-4 hours, with peak probability at 2-3 hours. Comments (article-anchored): most replies within 2-6 hours, with longer tail due to thoughtfulness required. Email: most replies within 1-4 hours during business hours, with sharp drop after 6 hours. The 2-3 PM window aligns with Scott H. peak probability zone, making it an optimal monitoring period for the cascade highest-value relationship.