How to utilize key user custom field "via CODE LIST" and "Custom Business Object"

[ai_takahashi]

Dear Product Experts,

I found two helpful blogs which states how to implement custom fields requirement.
I would like to clarify more how to utilize "CODE list via CDS view (developer extensibility)" and "Custom business object" options in case our customer wants to add their own custom fields in Accounting documents.

Technically, both option seems to be able to provide value help option by list. 

Key User Custom Fields: When to use what type of code list

Extensibility _how to implement Custom Fields using Coding Block business context in SAP S/4HANA Clo...

Thank you for your technical advice.
BR, Ai Takahashi

[Jerry_Lowery]

Hello Ai,

Could you please clarify your question?

Is it how to implement (concrete steps to take) or is it more looking for best practices?

Could you share more about the requirement?

Thank you

Jerry

[ai_takahashi]

@Jerry_Lowery 
Good day ! and Thank you for your reply.
The business requirements are...

1. to store custom fields into PL account line items in SAP system
2. to post accounting documents both from external front systems and from manual input in SAP
3. to have custom code list and its descriptions in SAP system for analytical reporting purpose
4. to update the master data of the custom field code list and descriptions coming from external systems such as project system and budgeting/planning system 
5. to enable the custom field value defined per company code, such as
   Company A - custom field YY_ZFI001 ... to be used for project code list
   Company B - custom field YY_ZFI001 ... to be used for budeting code list

I assume that the requirement other than last one should be covered by "key user extensibility".
But I am not sure if which technical option should suit the business requirement.

Thank you for your suppport and Kindly Regards,
Ai