Hello Board Community,
I would like to calculate projected stocks with the following formula : Stocks = Previous month stocks + current month Supply - current month Sales.
I have 3 cubes : Sales, Supply and Stocks. All cubes have 3 entities : Month, Part number and Market. Sales and Supply have values for 2019 (Actual before May, and Forecast after). Stocks has data for the four first months of 2019.
I have tried my hand at the rules, creating a 4D cube with a new entity (Data type : Sales, Supply and Stocks), and a rule [Stocks]=[.Stocks]+[Supply]-[Sales], applied in a layout were the columns are the months and the rows are the Data Types (see below)

Unfortunately, nothing changed for the empty months. I have run a few tests with the dot rule, and I can't seem to make it work with the time entity.
Am I doing something wrong?
Is there an easier way to calculate projected stocks?
Thank you for your answers!
Paul