ΔE 10.8, fair: the same colour family, but not a straight swap. Typhon Ash is noticeably darker than Glass Moon Light.
Can I use Typhon Ash instead of Glass Moon Light?
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Typhon Ash is noticeably darker than Glass Moon Light.
Can I use Glass Moon Light instead of Typhon Ash?
The same difference applies the other way round: Glass Moon Light is noticeably lighter.
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.