Nope, it sounds like someone who is trying to be clever with colour but it still doesn’t make sense to me.
Why would you mix a highlift tint containing bleach and a small amount of neutralising tint with a lower level tint? The bleach will presumably wipe out some of the colour pigment in the 8 and then won’t lift as high as it ought to?
If you want something around a 9, you could mix an 8 with a 10 but I don’t see the point in mixing a highlift with any other tint.