I read one of eBay's announcements:
eBay require all users to specify either Returns Accepted or Returns Not Accepted on the US, UK, Canada, and Germany sites.
However, on the AU and US Motors Parts & Accessories sites, eBay treat the "-- Select --" as Returns Not Accepted, so for these two sites, we can just leave the selection as is for those who opt for Returns Not Accepted.
US Motors site does not offer Return Policy.
To my knowledge:
We can only select either Returns Accepted or Returns Not Accepted on the UK and Germany sites, so on the preview page, other cells are blank.
The return policy section is always located in the 'Checkout Option' section, so we need to expand the 'Checkout Option' section.
We can now "Find & Replace" the return policy for listings all at once. We just select any listings on the 'Saved Listings' tab, click the "Find & Replace" button, and find the 'Return Policy' in the drop down menu.
Remember to select the "eBay Site" that matches the listings'.