New tax rates, page-225

Yeah Treasury modelling forecasts that an extra $28 billion will be collected over the next decade.
Their forecast has two elements.
Bracket creep that can be addressed in future budgets.
...and secondly extra hours worked (930,000 hours extra a week) due to reducing the 19% tax bracket to 16% which they say is likely to both encourage lower income people to participate in the work force and work longer hours.
So that would be for incomes that part time workers earn.
Maybe someone raising kids and balancing the extra income against cost of childcare.