Modification Concept for Personnel Calculation Schemas 
Use
Personnel calculation schemas are subdivided into standard schemas and customer schemas. Respective name ranges are not used to differentiate between standard and customer schemas. Standard schemas are client-independent, which means that they are visible in all clients. Customer schemas are client-dependent, which means that are only visible in the relevant customer clients.
You can create your own schemas or change existing schemas to adjust them to individual requirements. The modification concept describes the effects that result from the differentiation in standard and customer schemas for the processing of schemas.
Scope of Functions
SAP Standard Client
Only standard schemas are available. Each schema available in the SAP standard client is thus a standard schema, irrespective of the schema name. You can only change standard schemas in standard clients. You should only make changes to standard schemas if there are exceptions.
Non-Standard Clients
Activities
Standard schemas can change with each new release of the standard system. This does not initially affect customer schemas. However, it is important that you document your changes so that you can make changes to standard schemas in your customer schemas, if necessary. If you want to compare a standard schema and a customer schema for any differences, the
Comparison Function of the editor for personnel calculation schemas is available for this purpose.See also:
Name Assignment for Standard and Customer Schemas
Name Assignment for Standard and Customer Rules
Modification Concept for Personnel Calculation Rules