<prompt> Translate the following text to EnglishKwa hiyo, ni muhimu kurekebisha asilimia ya gharama za utoaji kwa ajili ya nafasi hizi kwa kiwango ambacho itakuwa na utoaji sita kwa wiki kama katika Marekani wakati asilimia ya gharama za utoaji ni kuongezeka au kupunguzwa kwa nafasi fulani, asilimia ya gharama za usindikaji wa barua hupunguzwa au kuongezeka ipasavyo.  <response>: Consequently it is necessary to adjust the percentage of delivery costs for these posts to the level it would be with six deliveries per week as in the U.S. When the percentage of delivery cost is increased or decreased for a given post, the percentage of mail processing cost is decreased or increased accordingly. 