You can find the entry for your unadjusted basis of assets immediately after acquisition (UBIA) as you continue in TurboTax. Once you enter your Box 20 code Z and the amount the screens shown below will follow. Select the check box beside UBIA and any other you may have on your supplemental schedule for the qualified business income deduction (QBID) or Section 199A. Once TurboTax has all the information the calculation will be accurate.