ΔE 43.1, loose: different enough that you should pick on purpose. Oblivion Black Wash is much more muted than Tyran Blue.
Can I use Oblivion Black Wash instead of Tyran Blue?
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 43). Oblivion Black Wash is much more muted than Tyran Blue.
Can I use Tyran Blue instead of Oblivion Black Wash?
The same difference applies the other way round: Tyran Blue is 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.