Well put as always space. I agree with everything you wrote. I was just throwing out some reasons (that I believe) why she was not feeling any love.

Value of collectibles is usually subjective. If she doesn't feel like she is getting what she perceives as fair then she should not sell. The market determines the objective price. If she doesn't want to sell her stuff at that price then I can respect that. For me when I sell things on ebay I start everything at .01 and let people decide what the item is worth. I have certainly lost money doing this but I have also made way more than I thought. That works for me and may not for her.
Obviously this community is going to have an increased knowledge of what faceplates are worth.

I was not privy to all of the pricing only the two that I asked about. It just appears to really be a buyers market. A good example is one of those Team Xbox sealed plates that went for 90 then 47 within a month. Again I hope she gets whatever she wants for them plus.