See my answer just posted for another user:
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I suggest to use the TaxCaster again and the amount shown should be closer. Developers fixed the issue as of January 25th, 2019. Is it possible that you filed your taxes prior January 25th, 2019? If so, then it is possible that you may have seen a difference in the TaxCaster refund amount and the actual refund received.
Now, if you are is still having issues, it could come down to data entry. The easiest way for you to see if something was entered incorrectly is by comparing the little pop-up menu at the end of TaxCaster with the Tax Summary in TurboTax. (Image - Click on the button down arrow)