Try...........
1] Helper H3, formula copy down :
=IF((A3="Grand Total")+(COUNTIF($I$3:$I$13,LOOKUP(2,1/(LEN(A$3:A3)=2),A$3:A3))>0),MAX(H$2:H2)+1,"")
2] S/n K3, formula copy down :
=IF(ROWS($1:1)<=LOOKUP(9^9,$H:$H),MAX($K2:K2)+1,"")
3] Item L3, formula copy across and down :
=IF($K3="","",INDEX(B$3:B$358,MATCH($K3,$H$3:$H$358,0)))
Regards
Bosco