Discount on Kindle Pre-Orders Of My Book

My book is now out on Kindle. Amazon’s US site is charging only $17.99 on pre-orders of the book before it is released on December 12, when it will be automatically sent to those who made a pre-order. https://www.amazon.com/Contest-Japans-Economic-Future-Entrepreneurs-ebook/dp/B0CP2NSGNN/ref=sr_1_1?crid=3AXS69W99JZSC&keywords=richard+katz+the+contest+for+japan&qid=1701352258&sprefix=richard+katz%2Caps%2C81&sr=8-1 The regular Kindle price is $23.99.

On the Japanese site, the Kindle price is Y3,948 and I don’t see any pre-order discount https://www.amazon.co.jp/-/en/Richard-Katz/dp/0197675107/ref=sr_1_1?crid=3CTC1FRXRX2IG&keywords=Richard+Katz&qid=1699749524&s=english-books&sprefix=richard+katz%2Cenglish-books%2C137&sr=1-1

I don’t know its status on other e-reader sites.

The hardcover is also available on Amazon but Oxford Univ. Press is offering a 30% on the hardcover. For details, see this post.