In the Tax Advantaged section of Asset Flow, the “IRA Account” button is used to keep IRA accounts for spouses separate. This is largely for tax purposes because the cost basis of all assets, for each spouse in an IRA, are considered in the cost basis determination.
If there is no cost basis, check the “Tax Deductible Contributions” box. Otherwise, the account will use all contributions in the first few years as a cost basis to offset the distributions, rather than spreading them out. Turning the button on will divide those properly.