Tiered pricing and profit markup by themselves have nothing to do with each other. Since you are confused between them, attempted to ask me this totally unrelated question, pretending to know what you are talking about, and have not been able to explain how your random question is related to SP selling this red mod set for $18 while Rag has been selling them for $30, let me explain them to you.
Tiered pricing is about the more you buy, the bigger the discount. SP have this tiered pricing because there is a fixed cost in setting up each run. So if you order more, the same setup cost can be shared across all the keycaps that are made in that run. That's why you don't get discount for making the same keycaps in the same profile, same legend, but different color, because different color is not consider the same run or setup.
Profit markup, in this case, is SP selling this set of red mod set, that were wrongly made, for $18 a set. While Rag is selling them for $30. Doesn't matter how many sets are purchased, it is the same price. Rag sells them for $12 profit each set.
You argue that he could have bought them for more than $30 a set and sell them at a loss. Anyone who has remotely been following how Rag has been running his so-called "group buys" would know that Rag would never do that. Actually, who would? Maybe Soarer would.
I would not be surprised if Rag bought them from SP for even cheaper than $18 a set. Say if he bought at the same price, he is making $12 a set. Question for you, Soarer, how much would you sell them for if you bought these sets from SP for $18 a set? What's the right answer? Now that is a relevant question to this thread, which is about selling a set of keycaps for $30 when the manufacturer sells them direct to customers at $18.