Formatting in excel failing with C Sharp

Question

Conditional row formatting is failing in excel sheet through my C# Code. I have 4 conditions based on which row color is applied in excel.

1. Condition One applies Blue color
2. Condition two applies Pink color
3. Condition three applies Green color
4. Condition four applies Yellow color

See attached image:  


When the color in Condition 4 is applied, it changes the last row color of Condition 3. Kindly advise.
Note: I am using Excel Interop version- 1.7.0.0.