Noob, continued... Specific Gravity Questions

You guys were super helpful on my last post, and I've done some searching and reading and couldn't find what I was looking for, exactly.

Specific Gravity, I did a 20% water change last night; and started thinking about the hydrometer I'm using... and realized I might have messed up my salinity levels!!

I'm running my tank at 75 degrees, and using a 'Resun Hydrometer' which says it is 'Temperature Corrected Readings'.

I took that to mean the way it was designed/built it would autocorrect for temperature... then I realized ... wait... start again.

Ok so I've been reading that my tank (FOWLR) should be between 1.0200 and 1.0250 , I've been assuming this is 'true' specific gravity" (adjusted for temperature) and not 'relative specific gravity' (as measured with a hydrometer calibrated at a different temperature)

So.. now... to my actual questions...

1) Does 'temperature corrected readings' mean I don't need to adjust to a different temperature? If not, where can I find what temperature the hydrometer was calibrated to?

2) Specific Gravity for FOWLR tank, range of 1.0200 to 1.0250 sound appropriate, and is this 'true' or 'relative' specific gravity?

3) Fish data sheets, are they using 'true' or 'relative' specific gravity for the sweet spots of the fish

4) Am I TOO worried about this, or NOT worried enough, how much does it matter?