When creating a benefit plan that starts after the end of the cost plan associated,
the IRR calculates when there is enough total benefit to cover the whole cost plan.
There can be 0 in the first months of the cost plan.
The main idea is that the benefit has to have enough to cover the cost plan and if they are running at the same time,
the cost plan totals have to add up until the point where the benefit plan can cover it.
When the benefit is in the future, the payback takes into consideration the whole cost plan date range plus the periods needed for payback.