Some years have 53 Sundays, which can affect the total amount due for pledges with a weekly frequency. The weekly amount due is multiplied by 53 instead of 52.
For example, the year 2012 has 53 Sundays. If a pledge has a date range of 1/1/2012 - 12/31/2012 with a weekly frequency and an amount of $100 per week, ACS calculates the pledge total to be $5,300. In a situation like this, you can edit the pledge so that the total is $5200, which reflects 52 Sundays instead of 53.
There are a couple of ways to change the pledge total amount.
Manually update the Total field
Change the dollar amount in the Total field to the desired pledge total. ACS recalculates the Amount field (amount due each week), but the total will be correct.
Change the Start Date
Change the Start Date. In the 2012 example, you would change the Start Date to January 2. Since January 1 (which is a Sunday) is not included in the date range, ACS calculates the pledge's total based on 52 Sundays, and the Amount and Total fields match the contributor's pledge.