MDX - for level zero I want the calc but for upper level members do the normal aggregation

This is my OnHandRCalc account MDX.

CASE  WHEN IsLevel(Date.CurrentMember, 0)  THEN
CASE WHEN Date.CurrentMember = [&NextDay] THEN 0
ELSE
CASE WHEN IsUda(Date.CurrentMember, "FDOM")  THEN
IIF ([Buying Status-Discontinued]>0,
[OHR_Seed_New_Input] - SLSR + NTRECR + SHRR + TRANSR - DSTR - DSCR - NETMDCLRR - NETMDOTHR,
[OHR_Seed_New_Input] - SLSR + NTRECR + SHRR + TRANSR - DSTR - DSCR - NETMDCLRR - NETMDOTHR - NETMDPROR
)

WHEN NOT IsUda(Date.CurrentMember, "FDOM") THEN
IIF ([Buying Status-Discontinued]>0,
([OnHandRCalc],Date.CurrentMember.PrevMember) - SLSR + NTRECR + SHRR + TRANSR - DSTR - DSCR - NETMDCLRR - NETMDOTHR,
([OnHandRCalc],Date.CurrentMember.PrevMember) - SLSR + NTRECR + SHRR + TRANSR - DSTR - DSCR - NETMDCLRR - NETMDOTHR - NETMDPROR