The Tax Detail Report is in today's dollars, but the calculations in this report start with nominal dollars and then are converted to today's dollars. The gradual reduction of the exemptions and the deductions is related to the indexing assumption behind the annual growth adjustment being made. This annual adjustment doesn't necessarily align with the plan's inflation setting. The federal brackets and factors are indexed by the chained CPI which tracks slightly lower than the CPI that is represented by your inflation assumption.  So it makes sense they'd be lower year over year.