After futzing with Sean Terrill’s MrMalty instructions for stepped starters for a few batches, getting annoyed and calculating them out by hand, someone pointed me to a calculator that figures the steps out for me!
This is probably old news for you guys, but in case it isn’t, check it out.
In White and Zainasheff’s Yeast they make the same mistake, using “doubling” when they meant “multiplication factor.” They do that in a few places throughout the book, so I wonder if that’s just some yeast guy convention that makes no sense.