<prompt> Translate the following text to EnglishHata hivyo, masharti mengine katika Kichwa 39 kutupa shaka ya hitimisho kwamba mamlaka ya Huduma chini ya 401 c 3 ni pana kutosha kujumuisha mabadiliko katika viwango au mail uainishaji kwa makubaliano tu.  <response>: However, other provisions in Title 39 cast into doubt the conclusion that the Services authority under a 4013 is sufficiently broad to encompass changes in rates or mail classifications by agreement alone. 