With regard to the 'KN4000' this topic was raised some time ago Larry

The number '4' is considered to be unlucky in Japanese culture, so they avoid it whenever possible.
Maybe '7' also is unlucky

Technics rather than Panasonic - probably just a marketing thing, although I believe some keyboards did bear the Panasonic label.
As far as the numbering system is concerned - confusing ? OK! - but a rose by any other name..........

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Willum