Hello , 

As your query is you want to know whether there is some differences between Percentile and Combine Score or whether both of them are same.

I would like to tell you that your percentile marks is your overall percentile that you scored in the subjects you opted . Whereas in case of combined score it includes the marks of ypur12th standard, your entrance exam rank and marks scored by you in the entrance exam.

The way of calculating both of the details is different and both of them have different aspects of use. 

Further,if you have any query regarding the same you can let me know in the comment section below.

I hope your query is solved.

Thank you.