It is unusual but most cards drop well under preorder price within a month of coming out. The innistrad were high and then drop to the $9-$10 range and most others. Especially this late they're already upping prices. You can guess and hope it pays off but still doesn't change the fact that unless you need the card right away it will almost always drop. Duals jumped from $10-$12 to around $15+ for most of them, like all preorders, if you wanted in you should have by now. Most are overvalued now. Not to mention some of your valuations that you're using are beyond silly. You really think vraska is worth anything near the $40 they preorder for? That's skewing your prices so hard on mythics and he's going to drop instantly from that point, even freaking ajani people were going apeshit for is under $20 now.
No, I don't. That's the entire point of my post. Please read it.