This function calculates the difference between the value of the current period and the opening value. (Current - Opening)
The opening value is derived differently based on the View parameter passed to the function.
If the View parameter is YTD, the opening value is retrieved from the last period of the prior year.
If the View parameter is Periodic, the opening value is retrieved from the prior period of the current year. If the current period is the first period of the year, the opening value is retrieved from the last period of the prior year.
If the View parameter is blank ( " " ), the opening value is based upon the default data view of the scenario.