The annual saving and withdraw report shows you the pattern of saving and withdraw needed in your planning model to keep your per-adult living standard smooth or even year to year.
There are some years where your income exceeds your spending and a saving amount is recommended. Other years you will have more spending than income; in those years you will be dissaving or withdrawing from your regular assets in order to keep your discretionary spending smooth.
Remember that you have set a dollar amount for existing regular assets (non-retirement assets). This report shows the running balance and the saving and withdraw pattern for those regular assets. You also indicated some assumed rate of return for that pool of money. This pool of regular assets is assumed to achieve your assigned rate of return on average through the years. If you assume 3.5% return, you are probably not getting that return at your local corner bank unless you are in some money market funds or some other investment strategy. Typically these funds are in a brokerage account in order to use bonds or other investment strategies to achieve the 3.5% nominal rate (or the 1% real rate if inflation was set to 2.5%).
The interest or earnings for this pool of assets is shown current-year dollars in the Income Overview report. Often this interest earnings, this income, though reported as income to the IRS in nominal terms, is simply reinvested in the account (not withdrawn). In a year when there is saving recommended, the earnings income is reinvested or allowed to remain in the brokerage or saving account, it counts as saving that year. Earnings or interest unspent equals saving. And if your Annual Saving and Withdraw report says you should be saving, remember that in most cases, as just described, this interest earned counts toward this saving target. In other words, if your Annual Saving and Recommendation report says to save $4,000 but you also notice that your Income Overview report show that you have $4,000 in interest, you don't need to save the $4000 assuming that you do not withdraw your interest earnings from your regular asset account. A simpler way to think about it is to note that if you receive the income you indicate you will get in the program, and if you limit your spending to the spending shown in the Spending Overview report (which includes discretionary spending), the saving or withdraw will take care of itself because Total Income - Total Spending + or - Saving / Withdraw always equals $0 in any given year.