When switching from inherited and custom progress calculation, the options in the dropdown change from the inherited values to the previously entered custom values. I am typically only wanting to change 1 or 2 settings from the inherited settings, so having it keep those values and be editable would be a huge time saver.
The custom layouts section has a radio button to toggle from use inherited to custom. When using custom layouts, the row options for each record have the option to select a custom layout or retain the inherited setting.
Progress calculations (and record dates, whilst we're discussing it) need to have the same row-by-row, record-by-record option to inherit or have a custom setting. This will help with flexibility for users, guardrails for system control and makes sense for the consistency of the application.