TiBook power adapters not universal

[Simon Chapman]

My previous TiBooks (400, 550, 667) came with a variety of puck- and
cube-shaped power adapters, all of which - according to Apple - were
interchangeable. But the manual with my new 1Gb 15in TiBook states that
previous TiBook power adapters should not be used with this machine. Anyone
know why -- or is this just Apple being over-cautious to protect
themselves? TIA.

Simon