For the purpose of the UBIA calculation, include all items less than 10 years old that are not fully depreciated. If any item has been expensed through Section 179, but would not be fully depreciated if using "standard" depreciation methods, the Unadjusted Basis Immediately After Acquisition is essentially the original price you used to depreciate the item, and that is what is used for the UBIA calculation of all assets. UBIA is reported in box 17 with a code of X.
This amount can be used to help determine the QBI deduction, along with wages paid by the business, especially if the anticipated income is going to be above the Section 199A phase-out threshold for a non-SSTB business.
The QBI calculation is very intricate, but you do want to calculate the original basis all of the assets owned by the business in Box 17 with a code of X so that this calculation is passed-through to the shareholders. TurboTax will use this and all other qualifying income to help get the full amount of QBI deduction all are entitled to. This FAQ provides additional information on how it is is calculated: (open FAQ below and click on link How is QBI calculated (not for the faint of heart)?) https://ttlc.intuit.com/replies/7019998