I agree, after reading more closely, wildly is not correct. However, I rarely need 4 boards. Frankly, at least half the time, 2 OSHPark boards go unused.
They don't support 4L boards and minimum size in H or W is 1" (even 25mm gets rejected) I often have boards that are <1" on one edge. I will stick with OSHPark for the small stuff.