Repair Details cannot be populated for parent parts since they are not actually in stock. It is the children that are carried in stock. Therefore, this tab will be protected for parent parts. You will need to enter these details for each child part individually.
In addition, the fields on this tab have been reorganized to make it clearer which fields are related to internal repairs versus external repairs and which fields are necessary for both. New section headers have been added to make this more intuitive.