Just catching up here. I hit a similar brick wall when I asked for the MJT multiplier for each potential journey along with the zonal coverage that they supply at each fare change. As I understand it, TOCs have requested that details are no longer quoted outside the zonal area to avoid people gaming the system. The TfL Web page has subsequently been cut back to show duration across 11 zones whereas it used to go up to around 20 zones.
I did have some success in that I managed to get their website amended so that it no longer said that no refunds would be given if the maximum time was exceeded.
I’m currently chasing a query about contactless extension fares which I fully intend to take to London Travelwatch if I don’t get appropriate transparency.
Please do let me have any updates to your correspondence.