Hello,
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Look, if you are taking a drop for improvements then yeah it's a great idea, but see that your drop will not just be a time waste, if you are takinga drop then asure your self you will get higher score and if you are not sure then don't waste your time.
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Now for next year may or maybe the percentage will be same. There are 80% of chances for being same but 20% chances may or may not change the results as expected. So, just think twice and take a step accordingly.
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Once you put your decisions you shouldn't regret it

Hello,

As of now the announcement has been made for the year 2020 only and that possibly due to the fact that CBSE wasn't able to conduct all the examinations.

So we can't say anything that whether it will be continued or not unless the authorities do not update regarding the same.