Optional Variables in sequence still taking Format, even when not used.

[IncidentalProgrammer]

So this is probably a horribly sloppy code, but I'm still new to this, so please bear with me. I had this working yesterday, but then lost half a day's progress due to file corruption, and now I can't remember for the life of me how I did it, and now I'm so frustrated I can barely see straight, let alone program right.

This code runs a small form that generates names based on policy data that can then be pasted onto the policy document PDFs that we keep on file. I got some help with it here before, so it may be familiar. Yesterday, I made some tweaks to make some fields optional and attach formatting to them, and the problem I'm having now is that even when the fields aren't used on the form, the code still pulls the extra spaces, commas, wording, etc that's part of the formatting for if there IS a value, and throws it into the name. I had it working perfectly yesterday, so I know it can be done. What am I missing?

Private Sub btnFileName_Click()
     'Generates file name based on data in the generator.
     'Declare variables.
    Dim PolNum As String
    Dim EndNum As Variant
    Dim effDate As Date
    Dim desc1 As String
    Dim desc2 As Variant
    Dim desc3 As Variant
    Dim desc4 As Variant
    Dim desc5 As Variant
    Dim expiry As Variant
    Dim ExpYear As Variant
    Dim sFileName As String
    
    PolNum = Me.ctlPolNum
    ExpYear = Me.ctlExp
    effDate = Me.ctlPolEffDt
     
     'Endorsement number is optional.
    If IsMissing(ctlEndNum.Value) = True Then
        EndNum = Null
        Else
        If IsMissing(ctlEndNum.Value) = False Then
        EndNum = Format("End#" & Me.ctlEndNum)
    End If
    
     'Expiration extension is optional.
    If IsMissing(ctlExp.Value) = False Then
        expiry = Format(" Extend Expiry thru " & ExpYear & ",")
        ElseIf IsMissing(ctlExp.Value) = True Then
        expiry = Null
    End If
        
     'Description 1 must be provided.
        desc1 = Format(" " & Me.ctlDesc1)
    
     'Description 2 optional.
    If IsMissing(ctlDesc2.Value) = False Then
        desc2 = Format(", " & Me.ctlDesc2)
        ElseIf IsMissing(ctlDesc2.Value) = True Then
        desc2 = Null
    End If
    
     'Description 3 optional.
    If IsMissing(ctlDesc3.Value) = False Then
        desc3 = Format(", " & Me.ctlDesc3)
        ElseIf IsMissing(ctlDesc3.Value) = True Then
        desc3 = Null
    End If
    
     'Description 4 optional.
    If IsMissing(ctlDesc4.Value) = False Then
        desc4 = Format(", " & Me.ctlDesc4)
        ElseIf IsMissing(ctlDesc4.Value) = True Then
        desc4 = Null
    End If
    
     'Description 5 is optional.
    If IsMissing(ctlDesc5.Value) = False Then
        desc5 = Format(", " & Me.ctlDesc5)
        ElseIf IsMissing(ctlDesc5.Value) = True Then
        desc5 = Null
    End If
    
     'Format into name (policynumber(space)(space)end###(space)(space)effectivedate(year.mo.day) _
     (space)(space)descriptions.
    sFileName = PolNum & "  " & EndNum & "  " & Format(effDate, "YYYY.MM.DD") & " " _
    & expiry & desc1 & desc2 & desc3 & desc4 & desc5
        
    Me.ctlFileName = sFileName
    
End If
End Sub

[IncidentalProgrammer]

So of course, once I posted it, I remembered how to fix it. Replace "IsMissing" with "IsNull". Derp!