I have the impression that at least some people during the Napoleonic period saw writing just as a means to transmit sounds, not as a prerequisite for exact identification. If the sound of a name could be infered from the spelling, everything was fine.

I was told by someone who did studies about the Prussian general Yorck, that he sometimes signed his letters as "Yorck", and sometimes as "York".

And army lists - I am currently editing two hand written Prussian army lists of 1810. There are several (though not too many) variations in spelling of names. Certain names of Polish origin are sometimes written ending in -ky, sometimes ending in -ki, these suffixes seem to have been regarded as freely interchangeable.

One officer's name is written Seydel, Seidel or Seydell. The latter he used for himself when publishing a book, in later army lists of 1815 and 1817 etc., this latter spelling was used exclusively.

Another one is written in different army lists Diederichs, Dietrichs, Diederich, Diederichs. Maybe he was a numbler.

One officer was nobilitated by the king in 1799 with the name "Dittrich genannt von Schenck". In the army lists, he appears as "Dietrich genannt von Schenck".