I don't have either book in front of me, but I think that C&C adds the sponge in as a percentage total, rather than breaking it down to water and flour. In other words, the formula will say preferment 63% or whatever it is, and that will be 63% of the flour weight in the dough. Baker's make a distinction between sponge and dough. Everything in the sponge is referred to as the sponge side, and everything in the dough is called the dough side. So if your professor at Kump's says, what's the flour weight in the dough side, you'd look at that column in the formula. I'd like to know more about how to calculate the flour and water percentages in the preferments,but I find it confusing.
Just looked in Artisan Baking. She adds a preferment as a total unit too, at least in the sidebar explaining percentages. Once I got familiar with percentages I found it a lot easier to multiply formulas. For instance, I sometimes have to make French rolls for parties. I use Reinhart's French bread formula and it's really easy to figure out what the dough is going to weigh for say 240 rolls. I even made up a chart to make 50, 100, 150 200 rolls. But actually coming up with a new formula baffles me.
I used to be production manager at a bakery where we milled our own whole wheat flour and made a line of honey sweetened breads, I think we made 19 or 21 breads in all. I would wrack my brain trying to figure out the underlying principle in the formulas, but never could discern it. That was fun for a while, but baking like that is the hardest work I've ever done. Some nights there would be three of us to mix, shape, proof and bake 400 loaves, not to mention muffins, quick breads,cookies, brownies, croissants. I'd get to work at midnight, put the key in the door, and say How much longer, God, how much longer? I was so tired one night I got out of my little pickup and staggered towards the building,when behind me I heard a crunching noise and then a big bang. My truck had rolled down a small embankment and launched itself onto some railroad tracks, straddling one of the main westbound lanes out of Boston. I went inside and called the carabineri, and you should have seen how fast the tow truck guy whipped that truck off the tracks. Trains go by there at 50 mph. They tore off the muffler, and charged me 30 bucks.