I have a problem which includes the sentence:

The supplement for sales and administration is calculated as a percentage supplement on manufacturing cost. What does this mean? I am trying to calculate the full cost which, if I have understood it correct, means to calculate all the costs including sales- and administrationcost. I have everything else, but do not seem to understand the sentence:

The supplement for sales and administration is calculated as a percentage supplement on manufacturing cost.

A short description of what the problem is; A business which produces christmas decorations (the bulbs) produces 1 000 000 og big bulgs, and 2 000 000 of small bulbs. I have then gotten the information about fixed and variable cost which I had to calculate by using the information that 40% of each fixed and variable cost are used in producing the small bulbs.

The only value I have not calculated is the amount that goes in to producing the small bulbs by taking into account the sales- and administration cost and it is not 40%. The sentence that follows is the sentence I do not understand.