Sort of the same here and on the same trails as well. I started with a 45lb spring, which felt great initially but then I realise I had 10mm left no matter what. I did some fettling, couldn’t get anywhere so ordered the 40lb spring and fitted that. A couple of days on it and realised it was not for me. I was getting nearly full travel, but it just didn’t feel as supportive until I whacked on a ton of LSC and that made it feel horrible on the chattery stuff. The 45/lb went back in, I spent some more time faffing with it and eventually got it to a good place. Ended up some distance from the settings that it was when they sent it to me, but feels pretty good.
For ref I’m on a pike with a FAST damper in it, which probably played a part. It was setup great from them when it was air and I only ever changed a click or two. I think there’s a lot of personal preference involved with these things, as well as how you ride and weight the bike.
I had mine last april, so I think that was just about the time Vorsprung released the updated chart.
Maybe hold off ordering a new spring and just back the bottom out off completely and see how that feels and go from there. I know there’s only meant to be 10% or so between springs, but not sure what the tolerances are on those springs rates and the interaction between that and whatever damping cart is in your fork.