calculation based on date selction

[#1]

Hallo everybody,

I have to improve a dashboard calculating the movements on some accounts.

I have a beginning outstanding balance

Then two more colums: Credit and Debit

The last column (final outstanding balance) simply calculates the final result.

The problem is that at the moment the first column has only the values at first january 2012.

So the dashboard only works from beginning of the year to whatever other date.

I need it to work with whatever beginning date.

So - logically - if I select first of february, it has to calculate, as beginning outstanding balance, the closure at 31 january, and use it as beginning outstanding balance.

Any suggestion would be helful.

Please find attached my example.

Thanks a lot in advance,

Lorenzo