ΔE 23.5, loose: different enough that you should pick on purpose. A-28M Greyish Blue is much more muted than Interior Turquoise Green Soviet.
Can I use A-28M Greyish Blue instead of Interior Turquoise Green Soviet?
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). A-28M Greyish Blue is much more muted than Interior Turquoise Green Soviet.
Can I use Interior Turquoise Green Soviet instead of A-28M Greyish Blue?
The same difference applies the other way round: Interior Turquoise Green Soviet 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.