issue grand total

hey ! 

Another problem with Grand TOTAL

this is my measure 

VAR _SelectedExercice = SELECTEDVALUE(CalendarFiscal[ExerciceComptable])
var _TauxdeMarge = CALCULATE(maxx(Marges,Marges[Valeur]),Marges[Exercice] = _SelectedExercice)
var _TotalCA = [Total_CA]
var _MontantMarge = _TotalCA*_TauxdeMarge
return _MontantMarge

my data

Table DataCA link with table family (dataca.libfam = family.lib.famille)

Table Marge (year, %marge,libFam) (marge.libFam = family.libfamille)

VAR _SelectedExercice = SELECTEDVALUE(CalendarFiscal[ExerciceComptable])

this var is for determinate the good fiscalyear selected

var _TauxdeMarge = CALCULATE(maxx(Marges,Marges[Valeur]),Marges[Exercice] = _SelectedExercice)

this var is too keep the good rate 

var _TotalCA = [Total_CA]

this var to keep the "totalrevenue"

var _MontantMarge = _TotalCA*_TauxdeMarge
return _MontantMarge

this var _montantmarge, too have the marge amount

return _montantmarge, 

i used a matrix with rows = family.libfamille

i have a slicer with year (calendar table link with dataCA)

at the rows all is correct but the grand total is not correct !

thanks a lot