Last week, after realizing that some of my listings still showed first class shipping after I thought I'd changed them to ground advantage, I decided to bulk edit all listings to GA.
There were several listings for which I wasn't able to revise because they had open offers. @wastingtime101 was extremely helpful in walking me through the steps to bulk edit and explained that open offer listings can't be revised until the offer period ended.
So after the SIO offers timed out and expired, I went back to change the shipping on those listings that hadn't been revised.
I don't know whether it's a glitch or if this is as it should be but it appears that I can't change shipping until a listing has ended. It seems that having had offers prevents any subsequent revisions.
Is this as it is intended?
These are screenshots of the message, with the shipping method and price grayed out, unable to be changed:

devon@ebay , elizabeth@ebay
albertabrightalberta | Volunteer Community Mentor
"I can explain it to you, but I can't understand it for you."