ElseIf overwrites prior if

I have the following code and I think the ElseIf checks the same cells as the initial If and overwrites the cells the initial If altered. I assume this has to do with the difference in condition (string check vs. rowheight).

Any input to addres the problem is highly appreciated.

Dim row As Long
row = 2
Const colSelected As Long = 67, belang As Long = 71, colPref1 As Long = 74, _ 
colPref2 As Long = 78, colPref3 As Long = 82

Set rngOutput = WsStam.Range("FC2") 
Set opmerking = WsStam.Range("FB2")
    With WsStam 
        lastRowInput = .Cells(.Rows.Count, colSelected).End(xlUp).row 

    Do Until row > lastRowInput 

        If .Cells(row, belang).Value = "Nee" Then
            rngOutput.Value = 0
            opmerking.Value = "Geen Belangstelling"

            ElseIf .Cells(row, colSelected).RowHeight > 0 Then   

                Select Case .Cells(row, colSelected).Value 
                    Case .Cells(row, colPref1).Value 
                        rngOutput.Value = 0
                    Case .Cells(row, colPref2).Value 
                        rngOutput.Value = 1
                        opmerking.Value = Voorkeur2
                    Case .Cells(row, colPref3).Value 
                        rngOutput.Value = 1
                        opmerking.Value = Voorkeur3
                    Case Else
                        rngOutput.Value = 1
                        opmerking.Value = "Functiereeks"

                End Select

                Set rngOutput = rngOutput(2) 
                Set opmerking = opmerking(2)

            End If

        row = row + 1 

    Loop

End With