Organization and content of the business plan will evolve as it is prepared. For example, if the driving force of the plan is marketing or sales then a preponderance of the analysis and plan_of_action section will be more up_front and sales oriented in tone. With business plan's the world is your oyster; think from the center out to the edges and think outside of the box.
But your fixed expenses don't do this. They remain the same no matter what sales does. That's why it's call fixed. These are expenses like rent, taxes, utilities, phone, salaries, insurance, etc. A lot of business owners never consider this. They just lump all their expenses together. But you could never make an accurate plan if you combine all your expenses together. If you project your sales higher and want to know what your expenses will be, you have to separate your fixed and variable. So, thinking about this principle, let me ask you a question. If your sales grew 10% and nothing else changed, would your profit margin be higher, the same, or less? Profit margin is % of profit against sales