Why do you need to know these percentages? As your sales increases or decreases, your material cost, labor cost, and variable expenses will track accordingly. They will track very close to the same % as your current business. As an example, let's say your current sales is averaging 贄ꯠ per month and your material cost is averaging ฤꯠ per month. That's 20% of your sales (ฤꯠ ÷ 贄ꯠ = 20%). So, what would your material cost be if your sales were averaging 赨ꯠ per month? It would still be 20% but it would be 20% of 赨ꯠ or ุꯠ. So with these percentages, you can project your material, labor and variable expenses. See how it works?
It becomes easy to communicate your ideas to the people you interface with, who in turn can give you better ideas or complement the ones you have. Collect all the material to one place. Having a business plan makes it possible to have all your ideas and plans in one place. It becomes easier for you refer to it and to use it to develop your business. You become a more committed business person and even others people, like your prospective financiers, can easily regard you as a serious business person.