I notice this behavor when reading pressed dual layer discs with the BenQ 1640 (see first scan). While this disc is not the perfect disc, I don't think it warrants the whole second layer being read at 8x. See the Liteon 1693S scan below.
Also is it possible to increase the trays eject/load speed. It's terribly slow compared to my other drives, including the BenQ 1620. Maybe a two speed approach like LiteOn uses, where it starts off fast and then slows about half way out or in.