ΔE 15.6, loose: different enough that you should pick on purpose. Pale Grey Blue is noticeably lighter, more muted than Freezing Moon.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 16). Pale Grey Blue is noticeably lighter, more muted than Freezing Moon.
The same difference applies the other way round: Freezing Moon is noticeably darker, more saturated.
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 Freezing Moon on the colour wheel See Pale Grey Blue on the colour wheel
All matches: Freezing Moon equivalents · Pale Grey Blue equivalents