Historical data is generally updated in the material master record when stock is withdrawn from the warehouse. However, it is also possible to enter historical data manually, which then forms the basis of the initial forecast.
There are two types of historical data (consumption values) in the material master record: total consumption and unplanned consumption values.
Total consumption is the total of planned and unplanned consumption. For materials planned according to the consumption-based planning procedure, it is always the total consumption that is updated.
Unplanned consumption is only updated for materials that are planned according to MRP,
When withdrawing a material that is planned according to the MRP procedure on the basis of a reservation, only the planned consumption is updated. This value is not recorded in the material master record but, instead, it must be calculated by the user by subtracting unplanned consumption from total consumption.
This is how you enter consumption values manually:
The consumption values entry screen appears.
You can enter as many values as you want, both for total consumption and for unplanned consumption. Switch between the total consumption and unplanned consumption entry screens with Edit ® Unplanned consumption or Total consumption.
If you want to enter more values than there is room for on the first screen, press F23 to obtain further empty lines.

You can change the consumption values in any way required by your company using user exit EXIT_SAPMM61W_002.