The attached default PVWatts / Single Owner case has the following:

• 30% ITC that reduces federal and state depreciable basis
• $5000 Utility IBI that reduces federal depreciable and ITC bases

The depreciation table in the cash flow shows correct IBI reduction of federal depreciable and ITC basis for each depreciation class, but the total is zero instead of the sum of the reductions for each class:

The reduction is being applied correctly to each depreciation class in the depreciation calculations, so this only a reporting issue: The total reduction is reported for informational purposes only.