CMN.ATO.CTR.500306 occurs when item D of the Calculation Statement is less than the sum of Item 21 label A + Item 21 label B.
ATO SBR Specification
The total of Item 21 label A + Item 21 label B must not exceed Item D.
This ensures that you're not claiming more non-refundable R&D offsets than what’s available to carry forward.
Check your values:
Recalculate Item 21 label A and label B.
Confirm that Item D includes all eligible carry-forward offsets.
Adjust Item D, If Item D is too low, update it to reflect the correct total of carry-forward offsets.
Review prior year data, ensure the carry-forward amount from the previous year was correctly brought into the current year.