[Button] Insert row below, copy the formulas and make them correct.

Good day dear friends,

I would like to ask you for assisting me in my problem.
For the last few days I am trying to add a button that will insert a row below the button and copy/stretch the formulas on all the rows.
When I just insert a row, the formulas on column L and M are not coppied right and I get a green arrow in the left up corner so i can correct it.
Problem is that i want to hide the M and N columns & don't want to correct it every time i insert a row.

I couldn't find any solution on the internet :<

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I have this formula, but seems like its not working and i just dont know why.

Sub copyRowToBelow()
    Dim rng As Range
    Set rng = ActiveCell

    Do While (rng.Value <> "")
        ' Insert a row below the current one
        rng.Offset(1).Insert

        ' Copy the current row and paste it into the row we just inserted
        rng.EntireRow.Copy rng.Offset(1)

        ' Set the range declaration for 2 rows below the current one
        Set rng = rng.Offset(2)
    Loop
End Sub

Thank you all in advance!

Szymon