You don't add it. You can't claim the deduction for overtime for overtime that is paid at the straight-time rate. Qualified overtime pay for the deduction is only the "half" in time-and-a-half. For example, if your regular pay rate is $20 an hour, and you were paid $300 for 10 hours at $30 per hour (time and a half), the amount you can deduct is $100 (the extra $10 per hour for the 10 hours of overtime).
