ΔE 11.7, fair: the same colour family, but not a straight swap. Middle Stone is a little lighter, warmer than Russian Uniform Lights.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Middle Stone is a little lighter, warmer than Russian Uniform Lights.
The same difference applies the other way round: Russian Uniform Lights is a little darker, cooler.
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 Russian Uniform Lights on the colour wheel See Middle Stone on the colour wheel
All matches: Russian Uniform Lights equivalents · Middle Stone equivalents