Help with my table - conditions

Dear All,

Please have a look at the following table. In the 2007/2008 tab or table two I have some formulae problems.

I want to take the sales value in B17 & apply it to the following commission scheme.

Whatever amount of sales the person makes I must subtract 4000 to arrive at the net sales figure.

From this net figure. We pay commission of 10% for the first 10,000 of net sales - 25%(B43) & 30% from 10,001 & above - 25%(B44).

I would like the 25% subtracted from these commissions to be inserted into B45.

Can anyone help?

Best wishes,

poshgaffer, Southampton, England