Amending a 2018 return's QBI

[RWG1950]

My software had not subtracted the 1/2 SE tax and SE ins premiums used as AGI adjustments before calculating QBI from "C" net income,
so an amended return will be prepared to reduce the QBI claimed for 2018.
Are there any additional forms required to be submitted in addition to the page 1 and 2 of the 2018 1040-X ?
My software provider includes form 8995 in their 2019 product but offered only a QBI worksheet for 2018.
Even through the software's April updates and final version, the 1/2 SE tax & SE ins premiums were still not automatically removed from the
QBI calculation - & they simply tell me that a manual adjustment is required. Been using this Co. for almost 30 years.
Not catching this QBI issue is on me, but considering what we have to pay for professional software, I had expected better from them.

[kathyc2]

I'd just show the corrected amount on line 4b and then put just put something like QBI not reduced for SE and SEHI.in explanation section.

But, are you sure the net QBI is different? There are situations where it would not be. Say client is single and only income is Sch C which is 50,000 calculating a 10,000 deduction. If the SE/SEHI was 5,000 the amount for QBI would have been 45,000 resulting in a 9,000 deduction. But since in this case that is the only income and the AGI of 45,000 would be reduced by the 12,000 standard deduction leaving 33,000 or 6,600 deduction. In other words, if there are no other items or income and the SE/SEHI is less than the standard/itemized deduction, the net QBI number will not change.

[RWG1950]

Kathyc2 :
Not sure that I follow what you have posted.
The stats for this MFJ senior retiree case per my calculations :
$ 19,900 net "C"
$ 123,336 total gross income (includes divs, pension, ss & cap gain)
$ - 1,406 1/2 SE tax
$ - 11,911 SE med ins
$ 110,019 AGI
$ - 26,600 standard deduction
$ - 3,980 orig QBI (should have been $ 1,317)
$ 79,439 orig T.I. (should have been $ 82,102)
$ 11,506 total tax (should have been $ 12,223)
$ 717 additional tax to be owed with the amended return
My software seems to tell me that amending is in order. Am I missing something here ?
I appreciate your comments.

[kathyc2]

No, in that situation the incorrect calculation makes a difference and return should be amended.

Where it may not make a difference is a situation where Sch C is the only income. Often it screws over a single person with Sch C as only income since with the deduction being after std/itemized deduction. If MFJ and spouse W2 income is at least std/itemized deduction the QBI is not reduced.

[Burke]

My software had not subtracted the 1/2 SE tax and SE ins premiums used as AGI adjustments before calculating QBI from "C" net income,
so an amended return will be prepared to reduce the QBI claimed for 2018.
My software provider includes form 8995 in their 2019 product but offered only a QBI worksheet for 2018.
.

My software also did not automatically compute QBI considering these deductions for 2018. The (included) QBI worksheet required the respective info to be input as well as a box checked to determine if it was a disqualified type of service business. If this worksheet did not have the correct information manually input by the preparer, it would not have resulted in a correct return. I am thinking a later update did have the figures on the worksheet, but you still had to check the box in order for it to feed through to the 1040 and calculate correctly.