Why did the ML gain so much weight in 2002?

[KyAl1013]

In looking at the published weight specs. for the ML, it shows that the 98-99 models were much lighter than the current ones. A little weight was gained in 2000, even more in 2002. I understand that many changes occured to increase luxury in 2000, but 2002 seemed more like a minor face lift, switch changes, etc. Why the weight gain?

http://www.whnet.com/4x4/specs.html