Recently, looking at a recipe for buckwheat levain bread from Dan Leader's book, Local Breads, I found online complaints about its percentages on the blog, The Fresh Loaf. I don't want to single out Dan Leader. He's a great baker, and also both honest and generous, as he was here, giving us an interview, and talking about the periodic mistakes made in the editorial process. From my experience, the editing in baking and cook books too often can get things wrong. 

Another top baker, for example, Jeffrey Hamelman ended up correcting one of his books with an errata sheet. And the latest book purchase I made, The French Culinary Institute's bread baking fundamentals book, has errors within the first chapter; its liquid levain baguette recipe has a percentage which is off about 30 percent. I found out by checking the math.

All to say, enjoy the recipes. But also, always read carefully, then do the math. If you find errors, and if you're informed on how baker's percentages work, try adjusting the formula. If all else fails, send an email to the editor or author (including me), because often you'll find honorable figures like Dan Leader or Jeffrey Hamelman, people who are passionate about their craft.