To say a device supports some particular format "thru conversion" seems to me like deceptive advertising. The device itself doesn't support those formats.
Almost any format can be converted to any other format with varying degrees of accuracy and effort needed.
The correct statement should be that a particular service or a non-kindle SW can convert from some formats to some other formats that are supported by kindle or that kindle+amazon service or kindle + calibre on your PC support those formats. Kindle alone doesn't support them.
Anyway, I'm sorry for the original confusion and sorry for this
rant