Extended dominance function
x(C_j,E_j) = EXD_j
Maps the expected costs and effects of options that survive the dominance screen, ordered by effect, to a flag for each intermediate option that a blend of its neighbours would beat.
Extended dominance condition for three ordered options
D_M = (C_M - C_L) / (E_M - E_L) - (C_H - C_M) / (E_H - E_M)
Cost of the blend that matches the middle option
p = (E_M - E_L) / (E_H - E_L); C_mix = C_L + p * (C_H - C_L); S_mix = C_M - C_mix