There is a big difference in the aluminum vs. the steel frame weight. The steel K5 frame weighs 19 lbs 7 ozs and the KX450f frame weighs 24 lbs 11 ozs. I weighed them with the same scale 30 seconds apart. There is no typo or mistake, the steel frame is lighter. The KX500AF is 5 lbs lighter than the KX450f. My AF frames are about 1 lbs lighter than the KX450F and probably most other KX500AF's. There you are and there you have it.
JFAB