I assumed the 2 APs you mentioned above - 回复：谢谢，那新的有效期应该是我这次出境一年

I assumed the 2 APs you mentioned above were issued at the same time, thus they have the same validity.

When you receive a new I-94 upon admission, the expiration date on it will be another 1 yr.

http://blog.wenxuecity.com/blogview.php?date=200710&postID=20710#AP