Audio PTS is not equal but play time is equal

[KaGaWu]

I have a video which has an dubbed Portuguese audio stream. The stream does not have the video head, like BGM of companies playing logos. So, the audio stream to delay some time play, it's first data package PTS is 9s. Then I transcode the audio stream to AAC, it's first package PTS is 2s. In my thinking the audio stream put the first data package in more front, it will play in more front originally, but it plays delay time is right!
Here is the first package PTS, origin and transcoded.

[Attachment 72463 - Click to enlarge]

[Attachment 72464 - Click to enlarge]


Can someone tell me why?

[KaGaWu]

Here is the video.
https://files.videohelp.com/u/302682/025_sisu_hevc_1920x800_30s_yuv420p_aac_copy.ts
https://files.videohelp.com/u/302682/025_susi_hevc_1920x800_30s_yuv420p_aac_trans.ts