I played around with this some more and now I’ve SOLVED IT! 😀
The problem is that the database works in a completely linear fashion, so you can’t ‘jump’ any steps.
What you have to do are the following 4 steps, all in Bulk Edit mode:
1. Allow Best Offer – change to – True
press ‘OK’ and run the edit
2. Auto Decline Best Offer – Change to – True
press ‘OK’ and run the edit
3. Auto Decline Best Offer Value Type – Change to – Percent
press ‘OK’ and run the edit
4. Auto Decline Best Offer percent – Change to – 75.00 (for example)
press ‘OK’ and run the edit
After completing all 4 steps it works!
The problem of course is that this is cumbersome and extremely time consuming. In my case, with 4,300 active listings to edit, working on a 30 MB broadband line, each of the 4 steps will take me approx. 6-7 hours to complete = total worktime min. 24 hours for what should be a fairly simple edit.
Logical thinking would suggest it would be enough to simply run the 4th step, but clearly that is not possible. Maybe something for the Sixbit team to look into?