Extended PDI custom field is not added to Data Workbench

Dear Experts,

I want to add a PDI created custom field to Opportunity in Data Workbench.

I have created an .xodata file for Odata Extension and choose the Opportunity Odata Service and select the custom field. I have save and activate the extension.

As I check in the metadata using the Service URL, I can see the field there.

However, when I download the Import file, it does not show the field in the template.

Did I miss any step? Did I use an incorrect Odata Service?