Curious About Japanese Blu-Ray prices for Season 2

Recently the Blu-rays for the second season were revealed and I couldn't help but notice that the volume 2 blu-ray (presumably akagi's arc/Nightingale) is 12000 yen compared to 9000 yen which seems quite excessive even if there is an extra episode. Would anyone have any information or knowledge as to why there is such a dramatic increase in price? Thanks a lot!

vol 1 - https://www.cdjapan.co.jp/product/ANZX-17711

vol 2 - https://www.cdjapan.co.jp/product/ANZX-17713