Inside the settings it says: 'This is a numeric value that determines the position of the custom field in the front-end and the back-end. e.g. 5' Nothing changes in the back end when I change this figure - please advise. Would be really great to be able to drag and drop arrangement order. ;-)
If you set custom field order to 5 then it will check whether fifth place is empty or not if that place is empty then file will display at that position otherwise it will display at the nearest empty place. Please check it again it will work.