As I look at this more, I don't think this is the problem. I think there's a bug. Here's what I see:
Under 'Australia', the columns I want have been customized:
Under Bullion Coins, I have the same columns:
Under 'Silver Kangaroo', I see a different set of columns, and no amount of adding, deleting, etc. will ever change that. It always stays the same.
I guess my question is, can I create a customized default set of columns that I see each time I add a new variety? Or can I copy / paste those settings from a good one to the current one?
I may not be describing this as well as I could. Let me know if you need more clarification.