If your refund was not what you expected you will receive a letter from the IRS explaining the change or offset.
There can be a number of reasons why your refund was less than the amount you expected. TurboTax does not receive feedback from the IRS regarding money that was offset from your refund. If you owed back taxes, child support, student loan debt, etc. you will receive a letter of explanation from the IRS in several weeks. The WMR site will contain a message regarding your offset. It is also possible that the IRS caught a mistake you made and reduced your refund.
IRS Treasury Offset Program Call Center at 1-800-304-3107
(Be aware also that your Federal refund and state refund do NOT come together)
Did you choose to have TT fees deducted from your Federal refund? (Remember that if you did that, you also agreed to an extra refund processing fee of $39.99)
How can I see my TurboTax fees? https://ttlc.intuit.com/questions/2565973