nope Turbotax is doing it correctly and it was doing it correctly last year so if you overrode any of its calculations you were in error. since it was acquired in 2020 and is 5-year personal property the 1/2 year (HY) convention applies since 40% of 5-year property acquisitions wasn't in the 4th quarter.
so while a full-year would be 40% of $400 the rules say you only get 1/2 year's depreciation the first year.
% of original cost allowed as depreciation each year (per IRS PUB 946 page 71)
1) 20
2) 32
3) 19.2
4 & 5) 11.52
6) 5.76
however, you may be doing something wrong. you should be allowed bonus/special depreciation = 100% of the cost
are you using type F for the type of asset
have you checked the box for economic stimulus qualified property (defined as:
Certain Qualified Property Acquired After September 27, 2017
You can take a 100% special depreciation allowance for property acquired after September 27, 2017, and placed in service before January 1, 2023 (or before January 1, 2024. Your property is qualified property if it meets the following.
• Tangible property depreciated under MACRS with a recovery period of 20 years or less.
if you want more information about depreciation look at the IRS PUB 946
https://www.irs.gov/forms-pubs/about-publication-946
