仔细读一下就知道这个理解是错误的

. Advance Parole Document.
1. If you are in the United States, you must attach:
a. ...
b. An explanation or other evidence showing the circumstances that warrant issuance of ana dvance parole document; or
c. If you are an applicant for adjustment of status, a copy of the USCIS or former INS receipt as evidence that you filed the adjustment application;

b的情况是适用于申请AP的原因不是调整身份的情况(指公共利益或人道主义紧急入境，c才是适用于I-485申请人
没有I-485收据，你解释什么也没有用，会被reject,要你补上I-485已经递交的证明。
解释的目的，是证明受益人符合人道主义或公共利益入境的条件，那种情况下，没有递交485也可以在境外直接 获签发AP