The Supply / Future Stock on Hand chart will plot your forecast stock on hand for each day of your forecast range. 

In general, the forecast will drop your stock on hand by the forecast quantity divided by the total number of days in the month. However, if you have an allocated transaction, or actuals within the month, the system will reduce the transaction quantity from your forecast quantity. If the allocated and actual demand quantity is higher than the forecast for that month then the forecast is fully cancelled out.

For example, if you forecast a sale to come in, you will see that the stock drops across the month by the forecast amount. If you then enter a sales order with an expected date to complete with the month that is equal to the forecast, then you will see the rate of demand adjust to zero. 

If this did not occur, you would see the stock burn-down each day according to the forecast and the open transaction, which is what the forecast was based on, also deduct stock on the day it is expected to go out. This would result in a required replenishment (or production planning) of both sources of demand. 

AIM will instead calculate an adjusted rate of demand to set the daily burn-down of stock.

The adjusted rate of demand will not drop the stock on hand by the remaining forecast, as this would result in steep dives of stock on hand in the last few days of a month for products that have underperformed. This would trigger required replenishments for these products, when actually the product is proving to be unpopular. 

Example: 

A product has sold more than the forecast: (green actuals is above the blue forecast)

Therefore, the rate of demand for the remainder of the month is zero: