Please see the attached workbook. We are using the lookup formula which lets us take the value from another part of the table and use it. In this case we are shifting left and that means we can use the lookup function. Depending how far left or right you are using the function you just need to adjust the last part accordingly.
ShiftedLineGraph.twbx 1.2 MB
I am not able to view your workbook. Its saying "Errors occured while trying to load the workbook. The load was not able to complete successfully".
I am using licensed Tableau 8.2 , may be you have created the workbook in the latest 9.X version. So may be because of that.
Can you add the logic here ?