Hi Atul,
I'll share my experience here.
This process being exactly similar to the Customer Order (SD Module) + Production Order (PP Module),
the consultants at the implementation stage have provided the Sales Order and Production Order Route here.
Example:
The person requiring the spare part fabrication, will create a Sales Order (VA01) and a Production Order will be created (CO01) on this and processed.
All material movements will be there,
Inspection Type will be there, Inspection Lots, Usage Decisions etc.
My opinion is your query of costing and accounting purposes will be addressed in this route only.
Other details
The Machine shop which fabricates these spare parts, also Repairs Damaged Parts for customers.
This has been mapped as Refurbishment Order.(PM)
So what happened was, the Machine shop people were at big difficulty, in processing Orders and compiling monthly or periodical reports. They are having to work in 2 modules and having to deal with 4 to 5 SAP sessions always.
Recently, we have provided a solution to them through complex development, which reduced their difficulty by about 75%.
This issue was talked in the document below.
SAP Process in Machine Shops: Issues and Remedies
Hope this information helps you to some extent in taking right route while mapping.
Jogeswara Rao K