The IRS can catch some mathematical errors, but this doesn't happen much with returns by online tax companies, because their arithmetic is computer-correct. If you entered a number that causes a bad result, the IRS wouldn't (at first) have any way of knowing that the calculation was incorrect.
It is likely that you will receive your refund on schedule. If the IRS detects a mathematical error or an inconsistency with other filed forms, then they will usually write you a letter (later) adjusting your tax and asking you to accept the adjustment.
You already know to wait for your refund in order to file your amended return.
