Your use of the Lehmann dough calculating tool was correct. However, your correlation of four 8" pizzas to two 16" pizzas is not. The reason is that the Lehmann tool is based on the surface area of the pizza, which is not linear based on diameter. For example, the amount of dough needed for a single 8" pizza is calculated by multiplying Pi (I use 3.14159) times the radius squared (4 x 4 in our example) times the thickness factor (0.10 in our example). That multiplication yields an amount of dough for one 8" pizza of 3.14159 x 4 x 4 x 0.10 = 5.026544 ounces. Using the same methodology, the dough weight for a single 16" pizza would be 3.14159 x 8 x 8 x 0.10 = 20.106176 ounces. So, the ratio is 4 to 1, not 2 to 1, as one might be inclined to guess when thinking linearly. Since the expression for dough weight is built into the Lehmann calculator, there is no need to wonder whether the results are correct. You tell the calculator what you want to do, and it will produce the correct results based on your inputs.
I might add that pizza operators often use a single dough ball weight to make more than one size pizza. For example, the amount of dough for a 16" pizza will make roughly two 12" pizzas. Similarly, the amount of dough for a 14" pizza will make roughly two 10" pizzas (which is often considered a "personal" size). The correlations aren't exact but close enough for practical purposes.