Norma,
I'm not so sure that the 10% figure wouldn't work although I can't say for sure since I have never used milk products at the 10% level. The lactose in the whey should give more crust coloration (with little sweetness) but I think it might be more even than if you used a fair amount of sugar in the dough instead where the combination of caramelization and Maillard reactions might be fairly extensive. The nonfat dry milk powder and the buttermilk powder would be used at reduced levels and, as a result, may therefore not pose problems. If worse comes to worse, you can always slip a pizza screen under the pizza if the bottom bakes up too fast.
I might add that I once tried to make a clone of the PH pan dough in the document I referenced and where I used a dairy blend. However, the amount of the dairy blend, which I put together as you apparently plan to do, was on the low side because I was trying to keep it in the right place in the pecking order. Also, I was using a fair amount of oil in the pan, which had a much more pronounced effect on final bottom crust coloration that the dairy blend. Alas, I was not happy with the results of the pizza overall so I didn't pursue the PH clone pan dough further. Having conducted so many reverse engineering/cloning projects since that time, I think I might be able to do a more competent job today. The downside is that the PH pan dough is now extinct, so there is little information left on that dough since PH went to frozen dough with an entirely different formulation reflecting the frozen nature of the dough.
Peter