Wait, do different people use the cousin words differently or is this page flat-out wrong? And not just wrong, but wrong about the exact term under discussion.
This page says Táng vs. Biǎo is based on whether it's on your father's side or mother's side. But the whole point of the "or" in MothersSiblingsDaughterOrFathersSistersDaughter is that Táng is for the children of two male siblings, and Biǎo is for the children of any other gender pairing.