Nippon-yasan is always gonna inflate their shipping sadly. I always do bulk combined orders in order to justify it since other shops in Japan automatically force EMS over $100-200.
Sometimes I use kurama online shop from JPY for single items because their single item shipping is pretty cheap compared to NY.
As for US stores, they don't custom order with large preorder windows. They decide how many they think they can sell and choose to stock whatever amount they order. Often times they sellout their preorders, but when they don't sometimes that stock just sits until somebody picks it up. I've bought old slow moving P-Bandai kits from all 4 before and all were legit.