The Washington Post reports that Freddie Mac will need to restate its profit for the first half of 2005 by $220 million "because of an error caused by faulty accounting software."  The company restated $5 billion in previously reported earnings in 2003.

According to the article,

The error stems from a flaw in the accounting program Freddie Mac has used since 2001. In a recent review of the company's accounting system, Freddie Mac employees realized the software was routinely overstating the amount of interest that the housing finance company earned from certain types of mortgage-backed securities that it bought for investment purposes, spokesman Michael Cosgrove said.

I just want to know--Why is it that accounting software glitches only seem to cause profit to be overstated and never understated?  Will someone please let me know the first time that they see a company announce that it is adding profit to its financials due to a software glitch?