Excel VBA to add + 1 to cell value only if not empty and not a formula

The following code adds 1 to every cell in defined range that has a numeric value. However it also overwrites values that are the result of formulas. It should only overwrite where the cell is a value and non empty but not when there's a formula.

Can I change it like this perhaps:

If IsNumeric(MyCell) And Not IsEmpty(MyCell) And Not IsFormula(MyCell) Then

For Each MyCell In Range("TrkLength")
        If IsNumeric(MyCell) And Not IsEmpty(MyCell) Then
        MyCell.Value = MyCell.Value + 1
        'MyCell.NumberFormat = "0.00%"
    End If
Next MyCell

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