... and so what would this tell you?

when I've used old paper, I get an increased base+fog i.e. I cannot get any 'whites' only some low level grey
as if the paper were heavily pre-flashed. So, my question is, what to do with this information? Can you quantify
the B+F and use that to reduce exposer/developement?

Or is it more like: 'nope, ain't gonna use that because it's not worth the effort' ? [which was my eventual decision]