The most difficult step in the analysis phase is the 5 Abstraction Test.
The goal of this step is to find out if ERP5 core model can represent the flows described in the interview. In the event some flows may not be modeled, Core Extensions to ERP5 may be required, if feasable.
This phase should be conducted by a business analyst with an experience of multiple implementations of ERP5 projects and may require help from the designers of ERP5 core.
For example, ERP5 flows only defined initialy the source and destination of goods in a trade transactions. However, companies with a distribution network require sometimes to know the final destination of goods sold through a distributor. This requirement ended up in an extension of ERP5 core to support traceable indirect sales or purchase.
In general, no extensions should be required. The standard ERP5 framework is normally sufficient to cover most business cases. However, since ERP5 is an ever evolving open source framework, it is not because the standard framework does not cover a specific business case that ERP5 should not be used. Extending ERP5 core is sometimes only a matter of hours or days for an experienced engineer. The cost of ERP5 extension is usually neglectable compared to the cost of implementing and configuring ERP5.
ERP5 implementors should therefore not hesitate in evaluating the cost of Core Extensions with the help of experienced business analysts and core designers.