Singer bought WW, and was either providing ongoing support - or cleaning out inventory. They sure didn't make the Singer W9 for all that long.
The same thing happened when Free took over New Home, it took a while before "New Home" was only a name on a Free machine.
Sort of like Remington taking over Marlin, took them a while to use up old stock and start producing Marlins with the quality control standards of Remington.