Foreign Sole proprietorship

[fpvt2]

If a person owns a foreign sole proprietorship, does he/she file Schedule C ?
In the foreign country tax return, a tax payer can use a "norm" calculation where he multiply the revenue by 30% to come up with the net income. So, the tax payer doesn't need to list by the expenses like advertising, utilities, etc.
In the US Tax return, is there a similiar thing like that ? Or, you always have to list the expenses individually ? Does the total of the expense and the COGS then have to match the 30% number that he writes on the foreign tax return ?
Thank you.