It is a marketing ploy used by all manufacturers to extend a model's life.
A '98 ZX-9R in Australia was either blue or green, in the U.S it was red or green.
In '99, Kawasaki released the red in Australia and called it a 'new' colour. I think they did the same for the blue in the U.S.
I bought a red/black busa, the only other option in Australia the copper/silver. In the U.S. black/grey, copper/silver.
Year 2000 should see a 'new' busa sporting red/black in the U.S. and black/grey in Australia.
Confused????? So am I, LOL....