ΔE 19.0, loose: different enough that you should pick on purpose. Bloodstone is noticeably darker than Aged Hide. They are different kinds of paint: Army Painter Aged Hide is a one-coat contrast-style paint and Formula P3 Bloodstone is an opaque base/layer paint, so they won’t behave the same on the model even where the colour is close.
Can I use Bloodstone instead of Aged Hide?
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Bloodstone is noticeably darker than Aged Hide. They are different kinds of paint.
Can I use Aged Hide instead of Bloodstone?
The same difference applies the other way round: Aged Hide is noticeably lighter.
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.