Sumproduct tiered rates

Dear all

I am struggling with what I believe is a fairly simple solution. I have a number of fee bands and rates at which they are charged. I want to be able to calculate the blended rate for different amounts by changing cell D1.

For example, for a value of 4,000,000, the fee should be 41,000. I understand that the formula is a SUMPRODUCT, but I cant get the figures to match!

Example attached.

Greatly appreciated.

Nick