Functionality of Profit Center and Cost Center
I am unable to understand the functionality of Profit center and cost center, I know that cost center represents area within an organization for which you will like to see the expenses for a particular time period. for example in an organisation we have three cos centers Accounts, HR and Admin. whenever you post an accounting document in FI you will specify the cost center to which the expense relates. but in some cases when you post an expense and give the relative cost center the profit center is also driven by the system. why is this behavior? i mean i have posted an expense not an income then why is system driving the profit center as well?
Profit centers are used if you want to see the profit of different area of your organisation. in what kind of postings we use profit center? and if we could use profit center to draw income and loss for a specific area why do we need segment reporting? and what is the difference between Segment and Business area. what i understood from their definition is that they are both same and use for same purpose.
I am totally lost in these concepts. please some one help me out with an example. i am stuck at this point. some one please clarify my concept of Profit Center, Cost Center, Segments and business area please.