Richard, we have a lot of Kanban teams and had a requirement similar to the one that you describe, as we wanted to meaure cycle time between specific Kanban states. In some use cases we had multiple Kanban states (including Live or Deployed) that all mapped to Accepted, and the only way to get the dates there was to use the Lookback API. Since developing against the LBAPI was beyond our current BI capacity we had Agile Central Tech Services build a custom Cycle Time app for us and it works quite well. We've found the time and cost of working with Tech Services to be very reasonable so you might consider the same. Hope that helps.