This article explains the columns in the Plan Budget Forecast.
The first column is the name of the support category which that line relates to.
Budget Amount is the total amount for the budget category.
Average Daily Spend is
the total amount spent divided by the amount of days between the
service contract's start date and the current date (or the service
contract end date if that comes sooner).
Contract Start Date is the value recorded in the service contract's 'start date' field.
Contract End Date is the value recorded in the service contract's 'end date' field.
Budget at Contract End Date is
the amount of funding which will be left in that budget category when
the service contract's end date is reached, if the average rate of
spending is continued.
Forecasted Budget Consumption Date is the date the funding will be exhausted
for that budget category, if the average rate of spending is continued.