Why did A Mu say that Xia Shu spent 30,000 yuan a night?

Why did A Mu say that Xia Shu spent 30,000 nights because of misunderstanding? According to the query of Douban film materials, A Mu only saw Xia Shu enter the hotel and knew nothing else, so he later said that Xia Shu's 30,000 yuan was a loophole in the play. There was a misunderstanding between them, so A Mu said that Xia Shu would spend 30,000 nights. Preface D is an action film directed by Liu Weiqiang and Siu Fai Mak, starring Jay Chou, Anne Suzuki, Edison Chen, Huang Qiusheng, Shawn Yue and Jordan chan. It was released nationwide on June 19, 2005.