The way I would handle this for 2023 is to enter 20% of the cost and set the business use at 100% you'll only get 11.5 months of depreciation for 2023 under the tax rules - mid-month convention. This continues as long as the property is rented. Then the date you start renting 100% you enter the other 80% as another asset again with 100% business use with an in-service date based on the date you put it out to rent. This should keep the Asset Life History correct
the other way is to enter 100% of the cost but 20% business use for 2023
for 2024 you'll have to manually compute the business use %
something like - days 20% rented/365 + days 100% rented (based on the date you put the other 80% out to rent)/365
then in 2025 assuming 100% rented you change the business use to 100%. the problem with this approach is that the Asset Depreciation History will assume the asset was always 100% rented from 1/1/2023 and thus the accumulated depreciation in the worksheet will be wrong.
there is a trick in Turbotax that you must use to be able to use ADS depreciation rather than standard MACRS
type of asset must be other type O
depreciation method ALT
