DEC 13 p5

Hi, Gromit I have question for paper P5 at DEC 13 regards to Q1, PART (v). when doing the plan B, I do not understand why the answer for Cheerful's contribution is the same each year? also in the scenario, there is sentence 'This is expected lead ............................and flat sales for Cheerful'. I do not understand what does the 'flat sales' mean? is the reason that the volume for Cheerful each year is the same? thanks ahead.