Invoice posting - which Dr's and Cr's are made?

Question

I am trying to understand how SAP posts standard invoices, from a Double Entry or T Accounting aspect. If I post an invoice to a supplier, I can see it posts a credit to the vendor account number, and a debit to a GL code, normally with a cost centre. If I run a Profit Centre report I can see the entry against the Profit Centre, is this a mirror posting, or is another entry involved? If so where does the opposite entry to that go.
I am trying to understand all of the debits and credits so it all balances.

Answer 1

Your point :
I am trying to understand how SAP posts standard invoices, from a Double Entry or T Accounting aspect. If I post an invoice to a supplier, I can see it posts a credit to the vendor account number, and a debit to a GL code, normally with a cost centre. If I run a Profit Centre report I can see the entry against the Profit Centre, is this a mirror posting, or is another entry involved? If so where does the opposite entry to that go.
I am trying to understand all of the debits and credits so it all balances.
Answer:
Basically you are trying to compare with FI and CO posting :
Assumption : in ECC6 with all settings done.
                                                             FI posting           CO posting (Real)             CO Statistical (PC)
Posting a vendor invoice for expenses
                                                              FI Doc                  CO doc                             PCA  doc
Dr Expenses A/c                                    Dr GL a/c           Dr to Cost Element             Dr to Cost Element                                                                               
(with cost center)              with Profit Center
Cr   Vendor A/c                                      Cr Vendor              No posting as it is not CE    Cr  Account
                                                              (sub Ledger)                                                    with profit Center
                                                             Cr GL a/c
                                                              (Reconc A/c)
Trial balance is taken for GL accounts and PCA Accounts which will tally.
CO document - which is posted from FI transactions of this nature posts only one side.
CO document which is posted from CO transactions will post both sides in CO. hence There is no TBal tallying in CO.
According to entries and configuration further - In CO, Cost element can post further more to different cost objects  like Internal order , profitability segments.-  But Only one cost object will become Real by SAP automatically to avoid duplicate allocations of cost and all others will become automatically statistical in CO - Prof Segment, WBS element, MTO Sales order, Prodn order, PMaint order, Internal order, cost center - cost center is the lowest object.
Hope this clear.