Internal Calculation Key (Control Functions) 
Use
The system uses internal calculation keys for the calculation of depreciation, imputed interest, and cut-off values (for information on the cut-off value key, see
Cut-Off Value). You enter internal calculation keys in the depreciation keys for these functions. The internal calculation key defines the parameters for the depreciation calculation program.Features
The graphic shows the control functions of the internal calculation key:

Internal Calculation Key
The standard calculation keys are an integral part of the system and cannot be altered. If you need to modify the key for legal or business reasons, you should copy the depreciation key and make the alterations to the copy. The key of the calculation key that you create has to begin with X, Y or Z.
For more information, see the FI-AA Implementation Guide under Valuation
® Depreciation/Valuation Keys.