Vous voulez dire:
Dim TotalVrt As Double
TotalVrt = WorksheetFunction.SumIf(Range("A2:A150000"), 6, Range("H2:H150000")) - WorksheetFunction.SumIf(Range("A2:A150000"), 7, Range("H2:H150000"))
TotalVrt = Format(TotalVrt, "#,##0.00")
MsgBox ("Le montant de votre...