When you use 53 for your reporting period on your transaction, the date entered for your Period Begin must be the first day of that period. It is also true that a Rep Period of 53 will never default in when you create a cost transaction. It must always be manually entered to be used and the correct beginning date chosen.
Typically weekly reporting periods only have 52 reporting periods. 53 is allowed as a way to accommodate leap years.
Here is an example of how the set up can be utilized for a 53rd weekly period.
Setup:
1. Reporting Periods: Weekly
2. No of Reporting Periods per Year: 53
3. First Date of Reporting Period 1: 1/01/2012
4. User Date: 12/25/2016
When I create my cost transaction with a User Date of 12/25/2016, 1 defaults in for the Rep Period and 12/25/16 and 12/31/16 are the dates. If I want this transaction to post to the 53rd reporting period, I must first change the Rep Period field to 53. When that occurs my dates are automatically changed but they are not correct. I must manually change the Period Begin date to be 12/25/16. When I do this, my Period End date goes to 12/31/16 and I can post my transaction.
Note If I use the VCR button to advance the period dates, my reporting period is set to 2.