{
  "method": "Invented serial arithmetic fixture, not a vendor account or delivery test",
  "date": "2026-10-20",
  "old_delay_hours": 72,
  "new_delay_hours": 24,
  "rows": [
    {
      "contact": "C01",
      "hours_already_waited": 0,
      "preserved_remaining_hours": 72,
      "recalculated_remaining_hours": 24,
      "restored_72h_remaining_hours_at_edit": 72
    },
    {
      "contact": "C02",
      "hours_already_waited": 6,
      "preserved_remaining_hours": 66,
      "recalculated_remaining_hours": 18,
      "restored_72h_remaining_hours_at_edit": 66
    },
    {
      "contact": "C03",
      "hours_already_waited": 24,
      "preserved_remaining_hours": 48,
      "recalculated_remaining_hours": 0,
      "restored_72h_remaining_hours_at_edit": 48
    },
    {
      "contact": "C04",
      "hours_already_waited": 30,
      "preserved_remaining_hours": 42,
      "recalculated_remaining_hours": 0,
      "restored_72h_remaining_hours_at_edit": 42
    },
    {
      "contact": "C05",
      "hours_already_waited": 48,
      "preserved_remaining_hours": 24,
      "recalculated_remaining_hours": 0,
      "restored_72h_remaining_hours_at_edit": 24
    },
    {
      "contact": "C06",
      "hours_already_waited": 60,
      "preserved_remaining_hours": 12,
      "recalculated_remaining_hours": 0,
      "restored_72h_remaining_hours_at_edit": 12
    }
  ],
  "recalculated_due_at_edit": [
    "C03",
    "C04",
    "C05",
    "C06"
  ],
  "preserved_due_at_edit": [],
  "new_contact_C07": {
    "arrival_hours_after_edit": 1,
    "due_hours_after_edit": 25
  },
  "rollback_limitation": "Restoring a delay cannot undo downstream actions already executed",
  "excluded": [
    "scheduler latency",
    "time zones",
    "business-day calendars",
    "send windows",
    "message content snapshots",
    "delivery",
    "concurrency",
    "permissions",
    "vendor API behavior"
  ]
}