I know that for those that are much more educated about guitar electronics than I am might find this a stupid question but I've just bought a 2006 SG Standard (NGD with pics coming soon) and it sounds absolutely phenomenal but when I roll the volume knob up, 3 sounds like 3 but then 5 sounds like 8 unlike on my 2015 where theres a distinct difference in volume every time I roll the volume knob up. I know its likely something to do with the pots but I thought I'd ask some people who know what they're talking about before buying new parts. The pickups are different to whats in my 2015 as well if that's at all a contributing factor
It probably has a linear pot fitted. Swap it for a log (audio taper in the USA) pot, and it will work smoothly.
Dude, you didn't tell me about it when the deal went down! Anyway, that sounds like you have a linear taper pot (as all Gibsons at that time did), which act as you have described. And, while you're at it, put some 500ks in there as well as they will open up the sound quite a bit, and actually make you want to use the tone control. Excited to see the NGD thread! And, keep me updated for when you closer to getting a Custom Shop!