I have plenty of salary income left over to pay for an expense I entered in the Goals & Additional Expenses section. I ham not yet retired. The expense starts next year. But this expense is being paid for out of my taxable investments and not my salary. Why is that?
You should only enter a goal/additional expense before retirement if the funds to pay for this expense will not come out of regular salary income. All expenses before retirement (Official Retirement Date Of The Plan) are first funded from contributions that would have gone to investments and then from the investments themselves. Note that the "Official Retirement Date Of The Plan" is determined by which spouse/partner in the plan retires first.
Example: If you have an expense before retirement such as utility payments that occur every year, you do not want to enter that in this section. The program will have already accounted for this expense since we assume that any income before retirement that is not saved is spent. However, if there is a one-time expense before retirement such as $15,000 for a wedding, you do want to enter that in this section as this large one-time expense will either cause your savings to decline that year, will cause a drawdown of investments, or both."