你的理解好像有误。

Any adjustment of status applicant who leaves the U.S. without advanced parole is automatically con sired abandoning his/her application for adjustment of status. Such a person will generally not be allowed back in the U.S. The person would have to do consular processing while remaining out of US. This applies to going to any place outside US, even going to Canada

以上的摘自http://www.immihelp.com/gc/aos/ap.html