D22 Navara changed towing specs

Quiet night tonight, so have been playing around/ researching.

Have found out that Nissan changed the unbraked towing limit for the D22 Nav. 2002 and 2003 models are rated at 3000kgs whereas the later 2004, 2005, and 2006 models are rated at only 2800 kgs. Tare Mass, GVM, GCM, are all the same. Does anybody actually know why? Can someone confirm the 2800 kgs on the later models by looking at the sticker on the RHS door?

Ian