@joshuabarksatlcs 

Cash OR accrual - had to be paid by 12/31/21 to get the deduction on the Federal return.  There are a few (smart) folks that think it *might* not be deductible until 2022 return as technically it isn't really a tax until the election is made - and that election can't be made until the filing of the return IN 2022.   

Spidell thinks it's deductible on the 2021 return IF paid by 12.31.21.  There's an IRS Notice (2020-75) that sorta/kinda addresses the issue, but it is not very clear (to folks who's brains can read/interpret that legalize much better than mine).  And IRS clarification isn't going to happen anytime soon.  

I had a few clients opt to pay by 12/31/21 to preserve the possibility of deducting it on the 2021 return - at worst it's a timing issue/cash flow issue.  

(edit - link added to just one of the many threads on the Spidell message board...)

https://www.caltax.com/forums/topic/ab-150-pmt-date-12-31-or-due-date-of-return/