[My response is] unresearched.  On 4/15 all you get is what's behind the cobwebs in my aging brain. 🙂

The first limitation you run into with S179 is the business income limitation at the entity level.  If it's limited by business income at the entity level, it doesn't make it out to the K-1 (it's carried forward until no longer limited by business income, then it passes out where the owner mixes and mingles it with other (potential) activities with S179 and applies the limits again at the owner level.)

In many ways this is an art form.  I've never been a huge fan of S179 carryover, and certainly not in an S Corp.  It's much more useful with a Sch C (where S179 offsets SE tax vs. Bonus depreciation fueled NOL which does not).  With PTEs you have to look at the big picture.  Is it beneficial to the owner to have a big loss in the first year (maybe they have other income they can offset)?  In many cases the answer is no.  With up-front write offs you're potentially "wasting" the lower tax brackets.  Saving 10-12% now is probably not worth paying 22% on that income next year (adjust brackets as needed, save 22% now, pay 37% later, etc.)  Fortunately we have LOTS of options in the tax code when it comes to fixed asset cost recovery.  What do the 3-5 year tax projections look like with Bonus vs. S179 vs. regular MACRS?  This is where 95% of the taxpayers are short-sighted and choose to save $1 now so they can pay $2 later.

The IRC also gives us the flexibility of filing an extension.  Why not wait until Aug/Sept and see how 2024 income is shaping up before deciding what is the "best" choice for 2023 depreciation elections?  That's what I would recommend to my client (doesn't mean that's what they'll agree to.)

Rick

(Edited to clarify)