Excel Commission Sheet

I need an excel sheet to work out commission payable on sales. We need to be able to add a range of products with variable profit percentages and then have the the sheet work out the amounts payable on each sale.

The commission schedule is attached. We have a qualifying period and then 3 percentage levels based on profits @ 5%, 7.5% and 10%. These figures are also influenced by 4 commission levels: 100%, 75%, 50% and 25%. The commission period is monthly.