2.3.9.3 Update Historic Volumes for Baseline Forecast

First let's try to understand what OFFSET does? It basically Pulls or Pushes the numbers across the timescale. There are three parameters that are needed in the Syntax 

OFFSET(x,n,z) where x is the source line item to offset

                               n is the offset value 

                               z is fill value if the result is outside the timescale

Result matches the data format of x - meaning it can be number, boolean or anything else.

FORMULA: OFFSET(1,-1,0) = 0

If you take a look at the left hand side of the formula OFFSET(1,-1,0) it basically throws an output of 1 in all the time periods except the first time period. That is because you are hard coding your first parameter to 1 and then you are asking Anaplan to Push it further by 1 period in the second parameter. Hence the first parameter which is 1 gets pushed to subsequent periods.

If you look at the overall formula now OFFSET(1,-1,0) = 0 it checks the condition and looks for a time period which has 0 in it and matches with that time period.

Now Let's take a look at Second parameter. Here the ask was to find out the first period of the timescale hence second parameter was kept  -1. If the ask is to find out first 3 periods of the timescale you can change the second parameter from -1 to -3 ( Its minus because we have to push the values to subsequent periods)

Note: First Parameter doesn't necessarily has to be 1, it can be any number apart from 0