I a table that shows interest compounding for a savings account.  A
variable amount of money will be taken out each month and that should
be taken into consideration.  As well as a variable amount possibly
being deposited.

The table needs these initial values:
- Current balance (say $10,000)
- Interest rate
- Number of months to calculate

Then I need a way to enter variations in monthly withdrawals.  Similar
to amortizing except I need to enter the payments manually and have the
table recalculate once I tab out of that month's payment box.  Or, I
could enter the payments initially as well.  Deposits should be handled
the same way.  Payments or deposits could be $0.00 for any month.

Thanks,
Brett