did you pay estimates? was you prior year's tax liability accurately entered? if the IRS data differs from what you entered, then there will be a difference between what Turbotax calculates and the IRS.
not sure this is covered by the accuracy guarantee, but you can always file a claim.
https://ttlc.intuit.com/turbotax-support/en-us/help-article/intuit-account-billing/submit-claim-turb...
