It does that. Look at the tab for spending models
Bernicke's Reality Retirement Plan: Start with the constant spending power model, but use Bernicke's "Reality Retirement Plan". Current age:
Note: If you indicate you are 56 or older, then the spending will be reduced immediately.
Ty Bernicke's Reality Retirement Planning: A New Paradigm for an Old Science describes extensive research showing that most people see significant reductions in spending with age (not related to reduced assets or income). If selected, this option will reduce your inflation-adjusted yearly spending by 2-3% per year starting at age 56, and then stabilizing at age 76 to keep up with inflation. You should read his article for details if you plan to use this option.