Is the number it uses for prior depreciation meant to show just last years depreciation or all total prior depreciation?
It shows the total of "all" prior depreciation taken.
, I looked at my 2022 tax return on Turbotax where I also depreciated rental properties. It shows depreciation in line 18 of Schedule E so I believe it correctly included the information last year.
Yes. Line 18 of the SCH E shows the total depreciation taken on all assets for tax year 2022. To see the total depreciation taken since the asset was placed in service, you have to look at the 4562 "that prints in landscape format" that is titled "Depreciation and Amortization Report". To get that specific form, you have to save everything in PDF format. Then you'll find it in the PDF file. The 4562 is only included with your "filed" taxed return in the tax years there is an addition, change, or removal of an asset from service.
If you want to check the math the program used (I encourage it) then see IRS Publication 946 at https://www.irs.gov/pub/irs-pdf/p946.pdf and use the MACRS worksheet that starts on page 36. For line 6 of that worksheet use table A-6 on page 71.
If your figures are off by a few bucks, don't sweat it. That's caused by "rounding" which the IRS allows.
