Perhaps this is happening?
When you have a very hot metal plate under the wet pizza dough, immediately water evaporates and in fact, a vapor layer separates the metal and the dough, making it unimportant the metal conductivity, because I would assume the temperature in that steam zone can't get above 212F.
However, the infrared radiation from the hot metal plate can penetrate the steam zone and heat up the dough at any temperature, not limited to 212F.
If the above is true, the thickness and conductivity of the metal may not be as simple as to how the dough is cooked/baked.
dcarch