How to design Expression or any other Way

Hello to All

The rate table which we use is as below:

From                To                       Rate

0                    1Lack                       0

1Lack             2Lack                    10%

2Lack             4Lack                    20%

4Lack             5lack                     30%

 

And if Our Sales Executive Achieve 150000 then we need to give compensation of 10% only on 50000 Amount because already till 1Lack it is zero.

And in second stage if our SE Achieve 250000 then we need to give compensation of 20% only on 50000 amounts and on remaining amount 2Lack we give 10%

And in the same way in 3^rd stage our SE achieve 460000 then we need to give compensation of 30% only on 60000 amount and on remaining amount of 4Lack we give 20%.

So how can I prepare expression or Farmula.Suggest me the way of doing this type of calculation?