Try to change your array formula in C3 by this one :
=INDEX('Forecast-Actual'!F4:X4,MATCH(E1,INDEX('Forecast-Actual'!F5:X6,MATCH(1,(A3='Forecast-Actual'!A5:A6)*(B1='Forecast-Actual'!B5:B6)*(B3='Forecast-Actual'!C5:C6)*(C1='Forecast-Actual'!E5:E6),0),0),0))
Regards
Bosco