ΔE 12.8, fair: the same colour family, but not a straight swap. Oxide Brown Dark is noticeably darker, more muted, cooler than Cypress Brown.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Oxide Brown Dark is noticeably darker, more muted, cooler than Cypress Brown.
The same difference applies the other way round: Cypress Brown is noticeably lighter, more saturated, warmer.
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 Cypress Brown on the colour wheel See Oxide Brown Dark on the colour wheel
All matches: Cypress Brown equivalents · Oxide Brown Dark equivalents