You can only edit on the site where the item is listed.
If listed on eBay.com, you must edit on eBay.com; if listed on eBay.ca you can only edit on eBay.ca. if listed on eBay.cafr you can only edit on Bay.cafr
I am using the bulk editor for the ones listed on .ca. When I amended my handling date to 2 days it dropped all the international plus US shipping. Now I can only amend one at as time. Cleared my cache and restarted but still having issues.