It depends on the rest of the tax return why taking the larger deduction reduces your refund. It is possible that you have credits that are larger with more income.
In such a case, it is ok to not itemize your deductions. When you are finished with the deductions and credits section, and TurboTax recommends using the standard deduction, select that you prefer to itemize your deductions.
Click this article for more detailed steps to change your deductions in TurboTax.
