It's an interesting question.
I think it's going to need some data padding.
Not sure if this will work for your true setup, but one method is to try is a crossjoin
to a single column of numbers in sequence up to 1000.
The crossjoin will make a thousand copies of each value, which we can then filter
down to the correct count using:
Now when a Quartile Reference Line is made, it should take into account the
number of copies of a value.
Please see workbook v10.3 attached in the Forum Thread.