39 CFR §3065.1

1. (a)The rules in this part implement 39 U.S.C. 601, which describes certain circumstances in which letters may be carried out of the mail.
2. (b)Notwithstanding placement in Postal Service chapter I of this title, the following provisions in parts 310 and 320 of this title are within the scope of this part and the Commission has the authority to interpret them:
   1. (1)Section 310.1 of this title;
   2. (2)Sections 310.2(b)(1) and (2) of this title; and
   3. (3)Sections 320.1 through 320.8 of this title.
3. (c)In the event of a conflict between 39 U.S.C. 601 and applicable regulations under parts 310 and 320 of this title, 39 U.S.C. 601 shall supersede any other generally applicable requirements.