The rules for calculating Substituição Tributária data are defined in two Customizing tables.

In the ‘Exception table’ data is maintained per ship-from and ship-to tax region combination, per material, and per customer group. In MM the customer group is always initial.

In the ‘General table’ data is maintained per ship-from and ship-to tax region combination and per customer group. In MM the customer group is always initial.

The system checks the ‘Exception table’ first. If an entry is found, this calculation rule is used. If no Customizing entry was found, the system checks the general table. If no calculation rule is defined in the ‘General table’ Sub.Trib. is not calculated.

The calculation type determines the base value for the Sub.Trib. calculation. Base value is either the ‘Invoice value (incl. ICMS/IPI)’ or a ‘Fixed price per unit’. If the calculation type is ‘Fixed price per unit’, the Customizing fields ‘Fixed price’, ‘Number of units’, ‘Unit of measure’ must be maintained.

If the calculation type is set to ‘No Sub.Trib. calculation’ the calculation for this specific parameter combination is deactivated. The calculation type ‘No Sub.Trib. calculation’ is only available for the material dependent calculation rules.

In SD, the base value is modified according to the definition in the ‘Special pricing conditions’. For each pricing procedure it is possible to modify the base value of Sub.Trib. by adding or subtracting condition values. The conditions defined in the ‘Special pricing conditions’ must be positioned before the tax calculation condition ‘IBRX’.

The possible base modifications are:

‘+’ Condition value is added/included into Sub.Trib. base

‘-‘ Condition value is subtracted/excluded from Sub.Trib. base

The surcharge rates is used to calculate a surcharge on the Sub.Trib. base value. The surcharge rate defined is applied on the base value for both calculation types ‘Invoice value’ / ‘Fixed price’.

Two percentage rates for base reductions which are applied to the Sub.Trib. base.

The ICMS reduction defined here reduces the original ICMS amount before calculating the Sub.Trib. value. The normal ICMS amount is not affected.

If the calculation type ‘Fixed price per unit’ is selected for the calculation of the Sub.Trib. base value, these fields must be filled. For the calculation of the Sub.Trib. base a unit conversion from the unit of measure entered here to the sales or purchasing unit of measure takes place. If such a conversion is not possible due to missing conversion rules, the tax calculation ends with an error and posting is not possible. The ‘Number of units’ defines by how many units the price is defined.

It is possible to modify the Sub.Trib. base value by adding or subtracting other condition values from the base value in pricing. The definition of these condition values is done in the Brazil specific SD Customizing of ‘Special pricing conditions’.

To have more flexibility regarding the conditions which influence the tax calculation it is now possible to define conditions, which are not relevant for the value transfer to Nota Fiscal. These conditions must have "NF value = ‘ ‘".

For all conditions defined in the ‘Special pricing conditions’ a modification rule for the Sub.Trib. base can be defined. The modification rules are ‘+’ (add to Sub.Trib. base) or ‘-‘ (subtract from Sub.Trib. base). Any condition, also statistical ones, can be used for that purpose. The only restriction for conditions influencing the Sub.Trib. base is, that they have to positioned before tax condition ‘IBRX’ in the SD pricing scheme.