We were comparing the average sea going vessel, regardless of whether it was a transport ship or naval ship. Bart claimed that Nanhai #1 ship is large for the typical Chinese ship. An average ship with such size would mean ships comparable to the average weight would not in fact be at the upper end of ship size regardless of what the typical warship weighed.The averaging of fleet's ship size is not very scientific: any fleet of any time consists of ship of different type and size.
And difference not only depends on ships availability, but also on tactical and strategical tasks: an invasion fleet must have a lot of big troop/supply carriers, but defending fleet does not need carriers at all- they need a fast and powerful warship, maybe of small size and coastal type.
Zheng He's fleet was close to former- it include a lot of transports (Bǎo Chuán, Mǎ Chuán, Liáng Chuán) escorted by warships (war Junks Fú Chuán and war galleys Zuò Chuán). Averaging will not give us any meaningful information about size of war ships.
On the other hand, during the Battle of Noryang, combined fleet of Ming/Joseon doesn't have any carriers- only war ships.