Marsha,
I think sometimes people not so much changed the spelling of their name,
but _accepted_ a change in the spelling.
In my husband's HAUSER family in Ohio 1825-1900, all the official county
land records, wills, and censuses spelled the name HOUSER, but the
tombstones are all spelled HAUSER, even for those who died in the 1940s.
The ones who then moved to Iowa show up as HOUSER and HAUSER and HOWSER.
I'm guessing it was just easier to accept a spelling change that have to
constantly correct the people (county clerks, etc.) And that's with a
name that wouldn't be difficult for English speakers to handle.
If my name were pronounced BANEY, as your gr. grandfather's was, there's
even more reason to just accept that new spelling. After all, the sound
was (basically) the same. I think pronunciation was more important to
them than consistent spelling.
I've been told that it's only in modern times (since the advent of Social
Security) that the precise spelling of names as become so important.
But of course, to those of us who use computers to access indexes of old
records, it's really a huge factor in finding our people :-((
Mona