using a calculated column for conditional column

i have an excel file with 5 columns: name, quiz1, quiz2, quiz3, and quiz4

the name column has the names of the students (unique) and each of the quiz columns have their scores for each quiz

after loading the table to power bi, i used conditional columns to group the scores into four buckets:

below 70
70-79.99
80-89.99
90 and above

from there, i was able to create a pie chart for each quiz to show how many % of the population got below 70, 90 and above, and so on


i need to do the same on a different dashboard but instead of an excel file that i can load into power bi, they have the scores on calculated columns. when i tried creating a conditional column using the calculated columns, they do not appear available in the query editor and not on the conditional column pop up itself.

is there a problem here and is there any workaround?