Why does spending capacity change when I copy a plan scenario without making other changes?
Discover how duplicating a plan scenario affects spending capacity and the underlying reasons behind this change.
Last published on: April 16, 2026
Why spending capacity changes
Spending capacity can vary slightly even when nothing in the plan changes because of how Income Lab calculates results.
When you use a Traditional Monte Carlo analysis method, the model runs your plan through thousands of “what-if” market scenarios. These simulations include variations in investment returns, inflation, and life expectancy.
Because these scenarios are randomly generated each time the plan runs, the spending capacity result can change a bit—even if all your inputs stay exactly the same.
When you copy a plan and only change the title, the system treats it as a brand-new scenario. That new copy runs its own independent set of simulations, with a different sequence of market outcomes. This is why you may see slightly different spending capacity numbers across copied scenarios.
What this means for comparisons
 Small differences are expected and are a normal part of Monte Carlo analysis. When comparing scenarios, focus on meaningful changes in inputs or larger differences in results, rather than small variations caused by simulation randomness.