Inventory cost calculation

Hello Tacir and Welcome to Excel Forum.
This proposal employs a helper column (V) which may be moved and/or hidden for aesthetic purposes.
Cells V5:V12 are populated using: =IF(S5=0,0,INDEX(F$4:F4,AGGREGATE(15,6,(ROW(F$4:F4)-ROW(F$3))/(H$4:H4>=-S5)/(B$4:B4=B5),1)))
Cells N4:N12 are populated using: =IF($L4>=0,L4*F4,-SUMIFS(V$4:V4,B$4:B4,B4))
Let us know if you have any questions.

Try pasting the following into cell M4 and copying down: =IF($L4>=0,L4*F4,-INDEX(F$4:F$12,AGGREGATE(15,6,(ROW(F$4:F$12)-ROW(F$3))/(I$4:I$12>=SUMIFS(G$4:G4,B$4:B4,B4))/(B$4:B4=B4)/(I$4:I$12<>""),1))*G4)
Also paste the following into cell N4 and copy down: =IF($L4>=0,L4*F4,SUM(M4*G4,SUMIFS(M$3:M3,G$3:G3,">0",B$3:B3,B4)))
Let us know if you have any questions.

It is good that you made the correction to the formula in column N and are getting the correct values. I am also glad to read that you do not see any other problems.
Please take a moment to mark the thread as 'Solved' using the thread tools menu above your first post. I hope that you have a blessed day.