yo sinceramente lo haria con (Form.Left Form.Top, Form.scaleWidth ó Form.ScaleHeight).
creo que para usar scaleWidth o scaleHeight hay que dividirlo por 15 (Form.ScaleWidth / 15) o (Form.ScaleHeight / 15) pero si queres Api, aca tenes:
Private Type RECT
Left As Long
Top As Long
Right As Long
Bottom As Long
End Type
Private Declare Function GetWindowRect Lib "user32" (ByVal hwnd As Long, lpRect As RECT) As Long
Private Sub Command1_Click()
Dim Win As RECT
Call GetWindowRect(Me.hwnd, Win)
Debug.Print "api: GetWindowRect: " & Win.Left, Win.Top, Win.Right, Win.Bottom
End Sub