I've a worksheet on Excel 2003 with table like below:

Incure Debt Date | Debt amount | Payment of Debt Date | Net
Financing
10/11/2007 1000 11/1/2007 =????
10/18/2007 2000 11/5/2007
10/25/2007 2000 11/15/2007
11/1/2007 2500 11/22/2007
11/8/2007 3000 12/1/2007
11/15/2007 100 12/9/2007
11/22/2007 5000 12/15/2007
12/1/2007 5200 12/22/2007
12/9/2007 2000 12/23/2007
12/15/2007 2500 12/24/2007
12/22/2007 3000 12/25/2007
--------------------------------------------------------------------------------------
Here, Net financing for 11/22/2007 is equal to: 5000 (Debt amount incured on
11/22/2007) - 2500 (Debt amount that must be payed on 11/22/2007),
so 5000 - 2500 = 2500 (Net Financing on 11/22/2007).

The question is, How I can automate it? Is there any possibility to do it
using PivotTables and avoid VBA programming? Of course I could create a
formula and copy it everywhere I need, but it would take time. If it is
solved only using VB, so how?
thanks a lot.