Using excel 2003 (SP3)

Cell "I6" is a calc dividing a retail target and how the person performed giving me a %. example 158%. Then the person belongs to a catagory eg: 1,2,3,4. Each catagory has a % target and a $$$ value assigned to the target.

Here is what I put together, but it will only calc the first incentive... if the % in "I6" changes to like 500%, the value is still the same? I did something wrong!

=IF(I6>='Incentives'!B3,'Incentives'!C3,IF(I6>='Incentives'!B4,'Incentives'!C4))

B3=100% on another tab

B4= $400

And so on...

Ideally it would be great if it was more like: if the person is catagory 1, and they are = or greater than 100% then apply incentives B3 (which is the $$$ value if over a certain %), then if the person is 125% then apply Incentive C3, if over 150% then apply INCentive C4.

I would just like to see what the $$$ is if someone is at a certain %.

Any help would be much appreciated!!!