<prompt> Translate the following text to EnglishKatika ECP, kuna nne: kuweka discount sawa na tofauti ya gharama rahisi kati ya makundi mawili; kuweka discount sawa na wastani wa kuongeza akiba katika  <response>: Within ECP, there are four set the discount equal to the simple cost difference between the two categories; set the discount equal to the average incremental savings in 