ΔE 15.4, loose: different enough that you should pick on purpose. Aluminium (Metal.) is noticeably lighter than Pale Silver.
Can I use Aluminium (Metal.) instead of Pale Silver?
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Aluminium (Metal.) is noticeably lighter than Pale Silver.
Can I use Pale Silver instead of Aluminium (Metal.)?
The same difference applies the other way round: Pale Silver is noticeably darker.
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.