I understand that it may well be technically incorrect. The exact verbiage for line 1 is of Schedule C is "Gross Receipts or Sales". My receipts, between Paypal, Direct Deposit and Checks deposited is very much like the totals off the cash registers in a retail establishment. In a retail establishment they would then deduct the cost of goods sold and returns. Of course I have neither of these but rather have amounts being reimbursed. If every company I worked for sent me a 1099 to 'prove' my income portion of receipts, I would be in great shape. The issue is that they do not. Thus my shopping does not really fit a Schedule C properly and it becomes time to try to make the full transaction activity as transparent as possible.
My gut feeling is that showing $12,000 as 'gross receipts' and subtracting out $6000 as reimbursements and $5000 for mileage and $600 for other expenses looks a lot more "real" as a 'legitimate business' than showing $6,000 as 'gross receipts' subtracting $5000 for mileage and $600 for other expenses, even though it gets to the same bottom line.
I gather that a whole lot of the audit process with IRS is automated to set up flags if 'line X is equal to or exceeds line Y or line Y exceeds line P by 20%'. Thus, philosophically, I want my 'gross receipts' to be as high a number as possible with the comfortable understanding that very few businesses show much of a paper profit once legitimate expenses have been deducted. The tax code over the years has been rigged to favor businesses and the wealthy, so the more one can use the tax loopholes opened for them, the better off one will be vis-a-vis taxes.