There is an option to retain metadata. I can't recall exactly how to
enable it at this point, I stopped playing with SFW a couple of years
ago. I still don't see the point of it, and your difficulties with
getting high fidelity JPEG rendering to your originals outlines one
reason why.
The mysteries of digital photography... Nobody asked
these questions when I was shooting slides!'
Not only did they not exist in the world of film and chemistry, they
were irrelevant since you couldn't replicate original slides with
much useful fidelity anyway. Digital images can be replicated and
distributed infinitely, which makes metadata and profiling much more
important. Your digital photos might be reproduced and rendered on
systems for many decades, it is good to have the accompanying data
defining the color rendering mappings and your ownership follow along
with them.
Godfrey