It's not clear why the account statement lists the tax withholding as a separate amount, but it really doesn't matter. What matters is what's on the Forms 1099-R since whatever was withheld for taxes is part of the entire gross amount of the distributions. It's likely that some or all of the distribution from the Roth IRA was nontaxable, so that might explain distributions totaling something close to $28,000 but only $21,668 being taxable. Perhaps the tax withholding was taken from the Roth account explaining why the nontaxable amount could be equal to the amount withheld for taxes.
You get the tax withholding back by it being credited on line 25b of Form 1040, placed there by TurboTax as a result of this amount being entered in box 4 of the Form 1099-R that included the tax withholding. By being credited on your tax return, the money is either paid back to you as part of your tax refund or it reduces the the additional amount that you would otherwise have to pay as part of your balance due.
Think of tax withholding as being roughly the same as if the entire amount was paid to you and then you sent an amount equal to what was reported as tax withholding to the IRS. If you send too much, you get a refund. If you send too little, you have to send more later as your the balance due.
