It is my understanding that for 2018 you can follow either the proposed or the final regs for QBI. How can this be acheived in Lacerte. QBI shows up on worksheet that it is being reduced by SE deduction, SEP etc. You can override the QBI for the calculation but it doesn't change the worksheet that is calculating QBI.
If you look at details of all the calculations, you will see that what you override as QBI for the activity (e.g. Sch C) will flow through to Loss Netting and Carryforward as well as the QBI Worksheet. However, QBI computations for the respective activities still show all the allocable deductions as if there is no override although these don't affect the actual QBID, which is an inconsistency.
As the previous discussion mentioned, even though the Proposed Regulations did not specifically state those as deductions, they DID say something like 'all deductions allocable to the business', which implies such things as SE deduction, SEP, etc.
