Hi aspirant..!!

I know it's a kind of confusing. But let's just take a scenario as you said you are dropper and if you qualified for jee mains there is obviously going to be a criteria for jee advance. So for that purpose you should going for cbse improvement. It will not going to harm you anyhow.

For further information you can definitely mail or call them. You can easily find contact details in  contact us section of jee website. All the best for future

Thankyou