ΔE 21.6, loose: different enough that you should pick on purpose. Kossite Flesh Wash is noticeably lighter, more muted, warmer than Reikland Fleshshade.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Kossite Flesh Wash is noticeably lighter, more muted, warmer than Reikland Fleshshade.
The same difference applies the other way round: Reikland Fleshshade is noticeably darker, more saturated, 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 Reikland Fleshshade on the colour wheel See Kossite Flesh Wash on the colour wheel
All matches: Reikland Fleshshade equivalents · Kossite Flesh Wash equivalents