There appears to be a Lacerte Depreciation Error that I am trying to confirm as the Lacerte programmers have indicated that the calculation is correct as is and vaguely referred to Form 4562 instructions and Pub. 946, neither of which addresses the discrepancy issue, other than tell us what the annual depreciation limit is under the luxury auto limitation rules, which is $19,500 for a 2023 placed in service vehicle depreciation cap in 2024.

Here is the issue - a 2023 vehicle was purchased  for $37,000 and placed in service on 3-6-23 using 5 YR 200DB HY MACRS method subject to limitations as it is a vehicle under 6,000 lbs and doesn't qualify for any of the limitation exceptions. In 2023 Lacerte, $20,200 of SDA leaving an adjusted basis of $16,800 for 2024. The 2023 Lacerte program shows that the depreciation for 2024 on its 2024 Depreciation Schedule should be $16,800 X the 2024 Sec. 280F limitation of .32 = $5,376. The 2024 Regular Depreciation Schedule says no that's not right, that "WHEN THERE IS UNRECOVERED BASIS, CURRENT DEPRECIATION IS CALCULATEC USING THE MACRS TABLE WITH A DEPR. BASIS of 7,400 TIMES THE TABLE RATE OF 0.3200 SUBJECT TO SEC. 280F LIMITS." This results in depreciation of 7,400 X .32 = $2,368 instead of $5,376. 

I have not found any justification for using $7,400 as the adjusted basis in 2024. I see that Lacerte is calculating that as 1/5 of the cost of the vehicle and I don't see in the Section 280F regulations, nor in the Pub 946, nor in the Pub. 463, nor in the 4562 instructions that the adjusted basis changes to 1/5th of the value of the asset. The 2025 Depreciation Schedule in 2024 Lacerte also is using an adjusted basis of $7,400. Whan I test this calculation out using $25,000 as the cost instead of $37,000, I get the adjusted basis as $5,000, which again is 1/5th of the cost of the asset.

So, either the 2023 Lacerte version of the 2024 Depreciation Schedule is wrong and 2024 Lacerte's version of the 2024 Depreciation Schedule is right, or vice versa as they both can't be right.

Where can I find justification for this 1/5th rule as Lacerte support and programmers haven't found it but is indicating it as being correct? I have searched everywhere it appears. I even tried using 4 different AI search engines (which you have to be careful with using as their answers can either be wrong or can change depending on when you ask the question), all of which tell me that there is an error in the  2024 Lacerte program, that the 2023 Lacerte version of the 2024 Depreciation Schedule is correct at $5,376,  and there is no justification for the Straight-line method of 1/5th the cost basis being used in the 2nd and subsequent years to calculate depreciation.