Same calculations on multiple columns

I am new to Power BI desktop and I am trying to conceptually understand the best way to tackle this problem. So I have a table that looks like this:

I want to perform operations that will done on each one of the seven columns. For example, one of the steps I want to perform is taking the average for rows 15-20 for every columns, so it will AVG1, AVG2,....AVG7. Then I will subtract from the average every value in the corresponding column. So for FIFO2_1, if average is AVG1 then the formula will be AVG - Xi (where i ranges from 0-30).

Next, I will search for the index of the highest value for every column, so it will be MAX1, MAX2,..., MAX7. Then I will take the index and get the average of the last 10 points, this again for every column. So you can see it's a sequential process and I am not sure what will be the best way to preform it. It's the same process for every column.

What I did until now is create a measure for every column and then divide the

AverageBetween400and440 = 
CALCULATE(
    AVERAGE('Table'[FIFO_1_1]),
    'Table'[Index] >= 15 && 'Table'[Index] <= 20
)

transformed_FIFI2_1 = 
VAR X= [AverageBetween400and440]
RETURN CALCULATE(X- SUM(Table[FIFO_1_1]))

My plan is to replicate this for every columns but honestly this is not efficient a all and I don't even know how to perform the next steps. Is there a way to automate the process for all the columns?