the best way to think about it is this
think of it being a tax to guarantee the set happening, the lower orders we make, the more risk sherry takes on to make up the order, the more we order, the lower his risk, and the lower his risk is the lower the tax becomes
in an ideal world it would be a flat rate price of cost of 400 sets divided by 400, but if we want that, we wont get any more gmk sets, i3oiler can offer the sets at gb cost because that benefits him, the more he sells to us prior to purchase, the cheaper the tier is for him to buy sets for himself and his store( this isnt a dig at him, its a great way of him doing things for both him and us)
sherry is running a business, the difference between the tiers is marginal, but that little bit on top of cost is the price of getting him as a business, to facilitate the service of getting these keys made, something we as a community are failing to do, right or wrong, this is currently the cost of admission, and i personally would rather have a gmk set than not have one