Checkbox linked to calcs

Hi, I'm trying to use a checkbox to either include a certain data point or
exclude it. If checkbox is checked, n=n-a, if checkbox is unchecked, n.

I tried running the following code, but it doesn't work. Can someone please
help?

Dim withMobile As CheckBox

If withMobile.Value = True Then

Range("U66").Select
ActiveCell.FormulaR1C1 = "=RC[60]+RC[90]+RC[102]+RC[114]+RC[126]-RC[108]"
Selection.AutoFill Destination:=Range("U66:U99"), Type:=xlFillDefault

Range("V66").Select
ActiveCell.FormulaR1C1 = "=RC[60]+RC[90]+RC[102]+RC[114]+RC[126]-RC[108]"
Selection.AutoFill Destination:=Range("V66:V99"), Type:=xlFillDefault

Range("W66").Select
ActiveCell.FormulaR1C1 = _

"=IF(FISCAL_YTD=""YES"",RC[-2]-RC[-1],IFERROR(RC[-2]-RC[-1],0))-RC[108]"
Selection.AutoFill Destination:=Range("W66:W99"), Type:=xlFillDefault

Range("L66").Select
ActiveCell.FormulaR1C1 = "=RC[60]+RC[90]+RC[102]+RC[114]+RC[126]-RC[108]"
Selection.AutoFill Destination:=Range("L66:L99"), Type:=xlFillDefault

ElseIf withMobile.Value = False Then

Range("U66").Select
ActiveCell.FormulaR1C1 = "=RC[60]+RC[90]+RC[102]+RC[114]+RC[126]"
Selection.AutoFill Destination:=Range("U66:U99"), Type:=xlFillDefault

Range("V66").Select
ActiveCell.FormulaR1C1 = "=RC[60]+RC[90]+RC[102]+RC[114]+RC[126]"
Selection.AutoFill Destination:=Range("V66:V99"), Type:=xlFillDefault

Range("W66").Select
ActiveCell.FormulaR1C1 = _
"=IF(FISCAL_YTD=""YES"",RC[-2]-RC[-1],IFERROR(RC[-2]-RC[-1],0))"
Selection.AutoFill Destination:=Range("W66:W99"), Type:=xlFillDefault

Range("L66").Select
ActiveCell.FormulaR1C1 = "=RC[60]+RC[90]+RC[102]+RC[114]+RC[126]"
Selection.AutoFill Destination:=Range("L66:L99"), Type:=xlFillDefault

End If


End Sub

Thank you,

MK