Postings Made When Posting to a Previous Period 
When you post a goods receipt and invoice receipt to a previous period, the same postings occur as when you post in the current period:
At goods receipt, the system makes postings to the stock account and the GR/IR clearing account.
At invoice receipt, the GR/IR clearing account is cleared by the posting to the vendor account.
Automatic Corrections when Posting to a Previous Period
There are two cases in which it is necessary to make adjustment postings for postings to the previous period:
The system automatically carries out these adjustment postings when you post to a previous period. In these cases, therefore, two documents are created when the goods receipt or invoice receipt is posted to the previous period.