Database Query Returns Numbers as Text With ADO

Greetings, experts.

I created the following function to perform an ADO database query against SQL Server 2000 and return a disconnected recordset:

Function sql_select_rs(strSQL, objPassedRS)
      Dim objConn, objIncRS
      Set objConn = Server.CreateObject("ADODB.Connection")

      Set objIncRS = Server.CreateObject("ADODB.Recordset")
      objIncRS.CursorLocation = 3      'adUseClient
      objConn.Open MAILAPPDSN    'My DSN info

      objIncRS.Open strSQL, objConn, 3, 1, 1      'adOpenStatic, adLockReadOnly, adCmdText

      if Not objIncRS Is Nothing then
            Set objIncRS.ActiveConnection = Nothing
      end if
      Set objPassedRS = objIncRS

      Set objIncRS = Nothing
      objConn.Close
      Set objConn = Nothing
      sql_select_rs = true
End Function

The problem is whenever I try to perform any arithmetic in VBScript on numerical fields (i.e. bigint type), I get a type mismatch error. For example, the following gives the error with the above code:

blnReturn = sql_select_rs("select * from emails where email_id = " & strID, objRS)
nSent = nSent + objRS("total_sent")

but nSent = nSent + Clng(objRS("total_sent")) seems to work, even though total_sent is defined as a bigint.

Is this because I used adCmdText in the open statement? I don't want to have to convert every field to numeric if it is already a numeric field. Any idea why this is occurring and how to fix globally rather than explicitly converting each field to numeric after the recordset is returned?

Thanks!