This situation occurs when you have a pledge that is split, and one portion of the split is completely paid off, then the pledge is written off. The following example outlines how this functionality works:

Pledge: 20,000
Split Fund A = 18,000
Fund B = 2000

Pay 1500 towards Fund B
Write Off 10.00

The information for this Fund in the report will show as follows:
Fund B Pledged: 2000 Paid: 1500 W/O: 1.00 Balance: 499.00

If you change the payment amount from 1500 to 2000 it shows:
Fund B Pledged: 2000 Paid: 2000 W/O: 1.00 Balance: 0

The report will not allow a negative balance, so it does not deduct the write off amount in that specific case.

The way that the write off amount is calculated is based off of the percentage of the pledge fund split. In this scenario:
Pledge : 20,000
Split between:
Fund A : 18,000 (90% of pledge total)
Fund B: 2,000 (10% of pledge total)

Write Off: 10.00
90% of the write off is $9, so Fund A receives $9 as the write of amount in the report

10% of the write off amount is $1, so Fund B receives $1 as the write off amount in the report.