The custom data added to Change Scheme is not available through autotexts (there is no automatic autotext equivalent for all change scheme data, only name and ID), that’s why you can not make it work, unfortunately.
The reason Revision History objects can use custom change data is the following:
every new entry you create in Change Scheme is added to the global variable GLOB_CHANGE_SCHEME as a new header info, and the Revision History objects use that global for display selection settings (so no autotext are used there).
This global is available in every context, but the “pair” global containing the actual values assigned to each change are stored in LAYOUT_CHANGE_HISTORY, and that is only filled in layout context (since it only makes sense in layout). Revision History objects can display every change related to the current layout.
Technically all the same data is available for a change marker (or any object) as well, but since currently there is no “automatic” way to narrow the data to the marker’s assigned change only, displaying just the filtered info (Change Order of the connected change in your example) is not possible.