LINEST_R2 Straight Table

[EDehzn]

Hi,

I am trying to find the R2 values for each customer in form of straight table. I am using this expression currently

=LINEST_R2(TOTAL AGGR(SUM(Amount),Month),Month)

to get R2 value for each customer where the x-axis is total amount and y-axis is Month.

However the straight table  shows the same R2 for all customers.

How can I calculate R2 values for each customers?