Why is it important to distinguish between Financial Accounting, Management Accounting and Costs Accounting?

How do accountant accumulate and process costs data?. What are the difference costing system and how do they applied in different situation ?

What is the best costing system and costs classification that can be applied.? What is the hurdle in applying the system?

What is the impact of the different costing system applied on the businesss performance ? Why is different costing system result in different profit ?.