>I think the equivalent here is the IRS saying "look, these numbers look wrong to us. Please check them. We are not in the job of doing taxes for you".
The IRS doesn't usually do that, though.
If they suspect something might be fishy, they'll audit you and make you justify your reported return.
If they can see that you're a terrible accountant, there's a good chance they'll just send a correction, usually in the form of an estimated bill, but sometimes in the form of an unexpected check.
The dirty secret of American taxes is that unless you move a lot of money under the table, the IRS does already know how much you owe. But there are jobs that need protecting in the tax prep sector.