unusable QBI deductions do not carry forward. it's only qbi losses form separate activitie that gave not been used to reduce the QBI income
for example schedule c QBI $50,000. if it's not a SSTB tentative QBI would be $10,000 (subject to complete phase out if taxable income is too high) if SSTB and taxable income is too high that $10,000 is subject to phase-out so you may only have tentative QBI of $6,000 that too is subject to elimination if taxable income too high
no c/o in either xase
PTP has QBI loss $20,000 this would be a QBI carryover
QBI computed on form 8995/8995-A
