ΔE 10.6, fair: the same colour family, but not a straight swap. Mustard Brown is a little lighter, more muted than XV-88.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Mustard Brown is a little lighter, more muted than XV-88.
The same difference applies the other way round: XV-88 is a little darker, 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.
See XV-88 on the colour wheel See Mustard Brown on the colour wheel
All matches: XV-88 equivalents · Mustard Brown equivalents