<prompt> Translate the following text to EnglishHuduma ya posta inaweza kutofautiana sana na mifumo mingine ya posta katika gharama za kazi, automatisering, njia topography, kazi ya kugawana, mchanganyiko wa barua kwa umbo, na asilimia ya barua zisizotolewa, na kadhalika, hatuwezi kutarajia makadirio ya gharama zinazotolewa na mfano kuwa makadirio sahihi sana ya mifumo maalum ya nje ya Marekani.  <response>: Postal Service may differ greatly from other postal systems in labor cost, automation, route topography, worksharing, mix of mail by shape, and the percentage of non-delivered mail, etc., we cannot expect the cost estimates furnished by the model to be extremely accurate estimates of particular non-U.S. systems. 