We all have fixed expenses and variable expenses. As your gross sales increase, your fixed expenses (overhead) decreases. At the same time, your variable expenses will increase. The variable expenses(product, labor, fuel, ect.) would be zero if you did no work, therefore, variable expenses are a good thing. Bottom line, the higher your sales, the higher the profit margin. I am at about 55% profit.
I feel it’s important to realize the difference between employees and non employee business’s profit margins. When self cleaning I was between 66-73% annually. I my Manage/employee run area, it is about 15-20%. If the focus is on building the business, the profits will be better. IE: the set monthly expenses -vs- the operating expenses from cleaning. The amount of work plays the biggest part in determining the profit margins.