If your IRS-issued tax refund comes in around $35 or $40 less than the amount shown in TurboTax, it's probably because you used the Pay With My Refund service to pay your TurboTax fees. There's a separate processing fee for this service, which is deducted from your federal refund in addition to your TurboTax fees.
Please see this TurboTax FAQ on why your direct-deposit refund or check may be lower than what you expected: https://ttlc.intuit.com/community/refunds/help/why-is-my-direct-deposited-refund-or-check-lower-than-the-amount-in-turbotax/00/25594.The IRS will send you a letter of explanation when your refund is less than you expected you can also get this information by looking up your refund at the IRS Where's My Refund page.