Let's put it this way. When I "blueprint" an engine that's what I do, and it makes things work sooo much better. Now if they're claiming to do it to the rifle, then they'd better do it!
I think it's possible from my own experiences with JB that he does not use the term because that's not what he does. Otherwise by definition loads of BSA guns are leaving the factory out of design tolerance, which simply can't be right. If it is right, then they should damn well do it under warranty.