Bonus Tier Structure

I want a formula which takes into account both the amounts paid out per tier and net to the business. Basically the tiers would be 0-300,000 at 5% bonus, 300,001-500,000 at 10%, 500,001-750,000 at 15%, 750,001-1,000,000 at 20%. The bonuses would be based off the attorneys fees collected. The total paid to attorney would be a salary of 55,000 + the bonuses paid at each stage.