Question : After Update in Access

I am reposting this question as can't seem to solve and I may have originally not posted in enough areas:

I have a form where a user enters a client ID number [txtDBNO] as well as an item [comboitem]; the form is bound to table [tblCharges].   The code I''m using is supposed to look up the [txtDBNO] in the table [tblClient] and determine whether this client is supposed to be assesed [HasHandlingCharge] and if so it then is supposed to return the logical value [HasHandlingCharge] to the [chkHandlingCharge] and enter that into [tblCharges].

The users enter the [txtDBNO] first and then enters the [comboItem] and the code I'm using returns the correct value into [chkHandlingCharge].  And if the user changes his/her mind and changes the [comboItem] the code will replace the current contents of [chkHandlingCharge] correctly.

However, if the user is happy with what is in [comboItem] but realizes they have the wrong [txtDBNO] and changes it, the [chkHandling] does not change accordingly.  Puzzled and confused what I'm doing wrong.  I have two AfterUpdate routines... What am I doing wrong? How can I fix? Thanks! (AfterUpdate does mean after a change has been made to a control and you move to a different control, correct? Sorry for pedantic questions, I'm very much new to this). Thanks.

Private Sub comboItem_AfterUpdate()

If Nz(DLookup("HasHandlingCharge", "tblClient", "DBNO = '" & txtDBNO & "'"), False) = True Then
   chkHandlingCharge = DLookup("HandlingCharge", "tblItems", "Item = '" & comboItem & "'")
Else
    chkHandlingCharge = False
End If

End Sub
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Private Sub txtDBNO_AfterUpdate()

If Nz(DLookup("HasHandlingCharge", "tblClient", "DBNO = '" & txtDBNO & "'"), False) = True Then
    chkHandlingCharge = DLookup("HandlingCharge", "tblItems", "Item = '" & comboItem & "'")
Else
    chkHandlingCharge = False
End If

End Sub

Answer : After Update in Access

IMHO,tweaking the virtual NIC's bandwidth is not possible.