[AccessD] Cannot set recordsource on Load Event

Greetings,

Im vexed by a problem Im having with a form.  A97.
On form A, I have a Do.Cmd etc, and passing an openarg value of 1 or 2.
On form B, I have an on load event to evaluate the openarg and set the recordsource.  This is obviously not working as the form opens with all the records displayed.  If I set the recordsource in the properties window, it works fine.  What am I missing?  TIA.

Form A
DoCmd.OpenForm "Audit Entry", acNormal, , Criteria, , , "1"

Form B
Private Sub Form_Load()
   Dim iBusUnit As Integer
    iBusUnit = Me.Form.OpenArgs
    If iBusUnit = 1
        Me.RecordSource = "Audit_Data_Med"
    Else
       Me.RecordSource = "Audit_Data_MH"
    End If
End Sub