ΔE 11.1, fair: the same colour family, but not a straight swap. Mechanicus Standard Grey is a little lighter than German Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Mechanicus Standard Grey is a little lighter than German Grey.
The same difference applies the other way round: German Grey is a little 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.
See German Grey on the colour wheel See Mechanicus Standard Grey on the colour wheel
All matches: German Grey equivalents · Mechanicus Standard Grey equivalents