ΔE 11.6, fair: the same colour family, but not a straight swap. Temple Stone is a little darker, warmer than Underhive Ash.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Temple Stone is a little darker, warmer than Underhive Ash.
The same difference applies the other way round: Underhive Ash is a little lighter, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Underhive Ash on the colour wheel See Temple Stone on the colour wheel
All matches: Underhive Ash equivalents · Temple Stone equivalents