Hi Tony.  I have my financial model in Excel also with the monthly budget extending through 2016.  I'm not sure why I set it up for 120 months when I built it in 2006 other than that is when I will begin taking income from the retirment portfolio in the form of the RMD from my IRA. 

In addition to the monthly budget,  I also have three spreadsheets for each investment that I model: My IRA, my wife's, and a non-qualified taxable account.  Each of these spreadsheets project dividends and NAV for the funds in which they are invested, and allow contributions and withdrawals from each fund.  The planning period extends through 2042.  The three spreadsheets are linked to a cash flow spreadsheet which is inflation-adjusted and extends to 2042 also.

Your spreadsheets sound like they're pretty elaborate.  How do you estimate dividends in future years?  I  multiply the current dividend percentage by the projected NAV by the number of shares.  Each year I increase the NAV by a conserative historical average which, of course, increases the dividends. For example, if the current dividend % on a fund is 4.5% and the NAV is $10.00, then in that year I will project $.45 for each share.  If I believe the fund's NAV will increase by 2% each year, then the following year the NAV will be $10.20 and dividend will be $.459.  I leave the dividend percentage the same for all years. 

When you said that in your projections you would not run out of money until age 98 it made me wonder more about my projections.  Maybe I have not been as conserative as I think I have.  With only 30% in equities I am amazed that the model projects more than adaquate cash flow.  In fact, we never have to sell any shares and in every year can reinvest all of the after tax proceeds from the taxable account.  I just have to wonder that maybe I have an error in the spreadsheets somwhere or poor planning assumptions.