ΔE 7.4, close: similar, with a visible difference side by side. Ink Sepia is a little darker, more saturated than Magnolia Brown. They are different kinds of paint: Army Painter Magnolia Brown is an opaque base/layer paint and Vallejo Ink Sepia is an ink, glaze or transparent paint, so they won’t behave the same on the model even where the colour is close.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Ink Sepia is a little darker, more saturated than Magnolia Brown. They are different kinds of paint.
The same difference applies the other way round: Magnolia Brown is a little lighter, more muted.
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 Magnolia Brown on the colour wheel See Ink Sepia on the colour wheel
All matches: Magnolia Brown equivalents · Ink Sepia equivalents