Thomas Kuriakose
You are missing the last argument of first IF that should be zero in my opinion, modified formula should be.
=IF(D$10<>0,INDEX(tblP1[Price 2],MATCH('Cost Sheet Details'!$C$6,tblP1[Parameter1],0)*D10)+IF(D11<>0,INDEX(tblP1[Price 3],MATCH($C$6,tblP1[Parameter1],0)))*D$11,0)...