Probably you see miniscule discount because you have only few loyalty credits and thus your supposed discount is very small compared to average price of your models, whereas your buyers might have been accumulated much bigger amounts of credits and get full blown discounts. Also let's not forget rather frequent and long lasting sales events when everybody has chance to buy your models 30-50% cheaper. Unfortunatelly, as you already noticed My Sales page doesn't show neither how mbig discount was used nor what program was used to obtain a model at a discounted price.
IIRC Eduardas or somebody else from CGT team said that they would want to adress this isue sometime in the future. Let's hope it won't take too long.