ΔE 40.4, loose: different enough that you should pick on purpose. Iceberg Grey is noticeably darker, much more muted than Mana Regeneration.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 40). Iceberg Grey is noticeably darker, much more muted than Mana Regeneration.
The same difference applies the other way round: Mana Regeneration is noticeably lighter, much 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 Mana Regeneration on the colour wheel See Iceberg Grey on the colour wheel
All matches: Mana Regeneration equivalents · Iceberg Grey equivalents