=SOMME(C7,E7,G7,I7,K7,M7,O7)-SOMME(B7,D7,F7,H7,J7,L7,N7)
@ recopier vers le bas=SOMME(SI($B$6:$O$6=$C$6;$B7:$O7))-SOMME(SI($B$6:$O$6=$B$6;$B7:$O7))
=SOMME(SI(MOD(COLONNE(B7:O7);2)*ESTNUM(B7:O7);B7:O7))-SOMME(SI((MOD(COLONNE(B7:O7);2)=0)*ESTNUM(B7:O7);B7:O7))