How to do an if code whit variables on VBA

Helloo, sorry if my english is not the best, but i need excel does a fuction if it finds that one value is greater than other one and both are changing in each row

this is the code that i have and it says the error is in the if row

Sub Macro3()

Range("P2").Select
Do While ActiveCell.Value <> ""
    If ActiveCell.Offset(-12, 0).Value > ActiveCell.Offset(8, 0).Value Then
        If ActiveCell.Offset(-12, 0).Select + ActiveCell.Offset(-8, 0).Select < 100 Then
            ActiveCell.Formula2R1C1 = "=VBAProject.Disponible.Calculo_disponible(RC[-12];RC[-4])"
        End If
    End If
    
Loop

End Sub

Thank youu