Sub MFC()
Dim v%, P As Range, a$
v = Val(Application.Version) 'version Excel
Cells.FormatConditions.Delete 'RAZ
'---1ère MFC---
Set P = [C1:AA5] 'à adapter
a = IIf(v < 12, ActiveCell, P(1)).Address(0, 0) 'références relatives
P.FormatConditions.Add xlExpression, Formula1:="=DECALER(" & a & ";-1;)=1"
P.FormatConditions(1).Font.Color = -16776961
'---2ème MFC---
Set P = [C6:AA10] 'autre plage, à adapter
a = IIf(v < 12, ActiveCell, P(1)).Address(0, 0) 'références relatives
P.FormatConditions.Add xlExpression, Formula1:="=DECALER(" & a & ";-1;)<>" & a
P.FormatConditions(1).Font.Color = -16776961
End Sub