I need a formula to calculate the payout based on cumulative sales once a breakpoint amount is exceeded.

[JCharacter]

Example:

	A	B	C​
1	Fee	Cumulative Fee	Payout​
2	$ 800,000	$ 800,000
3	$ 400,000	$ 1,200,000
4	$ 900,000	$ 2,100,000
5	$ 700,000	$ 2,800,000
6	$ 600,000	$ 3,400,000
	Payout Formula
	Cumulative Fee	Payout
	$ 0	$ 1,000,000	50%
	$ 1,000,001	$ 2,000,000	60%
	$ 2,000,001	$ 3,000,000	70%
	$ 3,000,000		80%

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</tbody>

Where the payout for cell A3 ($400,000) is $220,000 (200,000@.50 and $200,000 @.60)