.net APIに関する質問です。

ブロック参照のクリップ範囲を取得する際に、
GrxCAD.DatabaseServices.Filters.SpatialFilterDefinition.GetPoints()
(※1)で取得していますが、クリップの設定により下記の通り挙動が変わります。

※1 （外部参照クリップ境界の座標値を取得する方法）参照

①プログラムでクリップを設定(※2)した場合：
ブロック座標系でのクリップ範囲の座標値を返す。
※2下記ソースコード参照

Imports Autodesk.AutoCAD.Runtime
Imports Autodesk.AutoCAD.ApplicationServices
Imports Autodesk.AutoCAD.DatabaseServices
Imports Autodesk.AutoCAD.Geometry

<CommandMethod("ClippingExternalReference")> _
Public Sub ClippingExternalReference()
    ' Get the current database and start a transaction
    Dim acCurDb As Autodesk.AutoCAD.DatabaseServices.Database
    acCurDb = Application.DocumentManager.MdiActiveDocument.Database

    Using acTrans As Transaction = acCurDb.TransactionManager.StartTransaction()
        ' Create a reference to a DWG file
        Dim PathName As String = "C:\AutoCAD\Sample\Sheet Sets\Architectural\Res\Exterior Elevations.dwg"
        Dim acXrefId As ObjectId = acCurDb.AttachXref(PathName, "Exterior Elevations")

        ' If a valid reference is created then continue
        If Not acXrefId.IsNull Then
            ' Attach the DWG reference to the current space
            Dim insPt As New Point3d(1, 1, 0)
            Using acBlkRef As New BlockReference(insPt, acXrefId)

                Dim acBlkTblRec As BlockTableRecord
                acBlkTblRec = acTrans.GetObject(acCurDb.CurrentSpaceId, OpenMode.ForWrite)

                acBlkTblRec.AppendEntity(acBlkRef)
                acTrans.AddNewlyCreatedDBObject(acBlkRef, True)

                MsgBox("The external reference is attached.")

                Dim mat As Matrix3d = acBlkRef.BlockTransform
                mat.Inverse()

                Dim ptCol As New Point2dCollection

                ' Define the first corner of the clipping boundary
                Dim pt3d As New Point3d(-330, 400, 0)
                pt3d.TransformBy(mat)
                ptCol.Add(New Point2d(pt3d.X, pt3d.Y))

                ' Define the second corner of the clipping boundary
                pt3d = New Point3d(1320, 1120, 0)
                pt3d.TransformBy(mat)
                ptCol.Add(New Point2d(pt3d.X, pt3d.Y))

                ' Define the normal and elevation for the clipping boundary 
                Dim normal As Vector3d
                Dim elev As Double = 0

                If acCurDb.TileMode = True Then
                    normal = acCurDb.Ucsxdir.CrossProduct(acCurDb.Ucsydir)
                    elev = acCurDb.Elevation
                Else
                    normal = acCurDb.Pucsxdir.CrossProduct(acCurDb.Pucsydir)
                    elev = acCurDb.Pelevation
                End If

                ' Set the clipping boundary and enable it
                Using filter As New Filters.SpatialFilter
                    Dim filterDef As New Filters.SpatialFilterDefinition(ptCol, normal, elev, 0, 0, True)
                    filter.Definition = filterDef

                    ' Define the name of the extension dictionary and entry name
                    Dim dictName As String = "ACAD_FILTER"
                    Dim spName As String = "SPATIAL"

                    ' Check to see if the Extension Dictionary exists, if not create it
                    If acBlkRef.ExtensionDictionary.IsNull Then
                        acBlkRef.UpgradeOpen()
                        acBlkRef.CreateExtensionDictionary()
                        acBlkRef.DowngradeOpen()
                    End If

                    ' Open the Extension Dictionary for write
                    Dim extDict As DBDictionary = acTrans.GetObject(acBlkRef.ExtensionDictionary, OpenMode.ForWrite)

                    ' Check to see if the dictionary for clipped boundaries exists, 
                    ' and add the spatial filter to the dictionary
                    If extDict.Contains(dictName) Then
                        Dim filterDict As DBDictionary = acTrans.GetObject(extDict.GetAt(dictName), OpenMode.ForWrite)

                        If (filterDict.Contains(spName)) Then filterDict.Remove(spName)

                        filterDict.SetAt(spName, filter)
                    Else
                        Using filterDict As New DBDictionary
                            extDict.SetAt(dictName, filterDict)

                            acTrans.AddNewlyCreatedDBObject(filterDict, True)
                            filterDict.SetAt(spName, filter)
                        End Using
                    End If

                    ' Append the spatial filter to the drawing
                    acTrans.AddNewlyCreatedDBObject(filter, True)
                End Using
            End Using

            MsgBox("The external reference is clipped.")
        End If

        ' Save the new objects to the database
        acTrans.Commit()

        ' Dispose of the transaction
    End Using
End Sub

（参照元：https://knowledge.autodesk.com/ja/search-result/caas/CloudHelp/cloudhelp/2016/JPN/AutoCAD-NET/files/GUID-72029044-0840-4187-9A58-F2A4518E3A23-htm.html）

②IJCADのXCLIPでクリップを設定した場合：
全体座標系でのクリップ範囲の座標値を返す。

これはプログラミングに問題があるのでしょうか？

開発環境はVisual Staudio VB.net、IJCAD2016です。

お手数ですが、情報提供いただけますと助かります。