Hi Tushar- Julianne from Mixpanel Support here.
Diving right in, we recently released a feature to allow you to make Nth percentile calculations. The option can be selected under the percentile measurement. I've also generated an example of this in our demo dataset: https://mixpanel.com/s/1hpQuQ.
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Mixpanel Workarounds for 80th Percentile Calculations | Mixpanel Community