The accounting scandal that has landed Fannie Mae on the political hot seat might also raise some questions about whether the largest GSE in the nation made the best financial moves during the past four years. According to Fannie, the firm will have to wipe about $9 billion in revenue off its books for the period of 2001 to Sept. 30, 2004. Freddie Mac, on the other hand, was forced to recognize a $5 billion…