A huge thanks to Fluff and Jack for helping me get to where i am with my formula.
=SUMIF('[Production Plan.xlsx]Production Plan draft'!$C$8:$C$12,B138,'[Production Plan.xlsx]Production Plan draft'!$D$8:$D$12)/6+SUMIF('[Production Plan.xlsx]Production Plan draft'!$J$8:$J$12,B138,'[Production...