If the amount is $100 give or take, it "could" be the turbotax fees deducted from your refund. Otherwise, just because the IRS accepted your e-filed return, doesn't mean they agreed with it. So if it's not TT fees, that would indicate the IRS found an error on your return and corrected it for you.
When that happens, the IRS will send you a letter explaining what they changed, why they changed it, and instructions for what you are to do if you dispute their changes. It's generally 3-4 weeks after you receive your refund that such a letter will arrive at the mailing address you provided on the return.
