my highest is 82 percntile in dashcat mocks and i have achieved around 80 percentile 3 times , what approx percentile can i expect for Dday

dude , in an exam like cat , we can never guess one's performance based on the mock scores , in a section like LRDI a set of 5 questions are linked to one set , you get the set right you get 15 , you don't get the set right you get 0 , the margin is big and one small mistake in lrdi can make your exam go haywire and affect quant too . Having said that , there is also a possibility even if you're not doing well in mocks , you might to do great in the exam , so give mocks , analyse , grow through silly mistakes and go all out on D day , but don't extrapolate marks .

Great advice Blisstry. Don't try to extrapolate Mock scores to actual CAT. Rather use Mock scores to analyze and improve your weak points.