Excel Mac ignoring custom page breaks in VBA

[cc1987]

I use the below code to automate report production by looping through a named range.
It works fine on Excel Windows but on Mac it ignores the custom page breaks and applies a 37% scaling to the page also meaning a 3 page report turns into a 26 page report. Not sure why this is happening or if I need to explicitly set the page breaks and/or scaling within the VBA also?

Public Sub PrintToPDF_combo()
Dim folderPath As String

folderPath = Application.ActiveWorkbook.Path

Set Rng = Range("def_nam")

For Each c In Rng

    Sheet5.Range("c16") = c

    'Debug.Print sI.Name
    'add export to PDF code here
   With Sheet3.PageSetup
   
    .Orientation = xlLandscape
    .PrintArea = Sheet3.Range("A1:Ae279" & lastRow).Address

    .FitToPagesWide = 1
    .FitToPagesTall = 3

    End With

   'This prints to C directory, change the path as you wish

   Sheet3.ExportAsFixedFormat Type:=xlTypePDF, Filename:= _
    folderPath & "/Reports/" & Sheet3.Range("G4").Text & "_" & _
        Format(Date, "dd mmm yyyy") & ".pdf", Quality:= _
    xlQualityStandard, IncludeDocProperties:=True, IgnorePrintAreas:=False, _
    OpenAfterPublish:=False
   
Next

End Sub

Manually printing to PDF works fine on Mac and I have tried repeatedly setting the various print settings in the document but it just seems to ignore them when it comes to the VBA