There is a mistake on page 311 of the 13th edition of Money Troubles under the section titled "You Haven't Previously Received a Bankruptcy Discharge."
The text should read as follows:
You cannot obtain a Chapter 7 discharge if you obtained a discharge of your debts in a Chapter 7 case filed within the last eight years or obtained a discharge in a Chapter 13 case filed within the last six years (there are a few exceptions to this six-year waiting period).
You cannot obtain a Chapter 13 discharge if you obtained a discharge of your debts in a Chapter 13 case filed within the last two years, or you obtained a discharge of your debts in a Chapter 7 case filed within the last four years.