Digital BW, The Print

Hi.
Question in regard to these issues.

When first beginning use of soft proofing, I was astounded to see that
,when I had a file fully prepared for printing, the onscreen
appearance between views when switching the proofing view on and off
was not really all that much different aside from, of course, the
lessor dynamic range of the proof view. Presumably that is the whole
point of softproofing and what is being seen are the actual file
modifications for that particular paper/ink/printer profile.

Is this the same as others experience with softproofing?

I also assume that one should always retain a master nee: unadjusted
file and work with copies so as to avoid future difficulties if forced
to switch paper/ink/printer etc.

Thanks.
Duane