If you said the profit margin would be higher, then you are right. Why would your profit be higher? If you said because of the fixed expenses, you would be right. Your material cost, labor cost, and variable expenses would have gone up 10% but your fixed expenses would have remained the same. You brought in more revenue because of more sales and you spent 10 % more on material, labor, and variable expense to cover the extra sales, but you didn't spend any more on your fixed expenses. So, less overall expenses, would give you higher profit margin. Make sense? So, let's see how we would make a business plan that would show exactly how your business could give you the salary you want.
Besides, your friends may be 100% behind you in your new venture, but, in case you are hoping to involve others who have actual money to invest, you may need to be able to make a convincing case. Wouldn't it be nice to have anticipated possible questions and be ready with plausible answers? If you are risking your own money, that is perhaps even a stronger reason to do some indispensable planning.