*off-topic*

The Philips 1640 is a BenQ DW1620. That is most likely what you saw. Some users prefer to flash the Philips version of the drive using a BenQ firmware, thus making it a 1620. The Philips firmware is said to stink, and the BenQ firmware said to be good, which is why users choose it over the Philips.

The BenQ DW1640, on the other hand, is a different drive entirely, and cannot be flashed to a DW1620. So keep in mind that the 1640 mentioned in some posts may refer to its equal, the BenQ DW1620, and not the BenQ DW1640.

*/off-topic*

And remember that LS doesn't have to be used...it is just there if you want to use it. The burning capability of the BenQ DW1655 should make it appealing as it is. You can always wait for the DW1650, just a non-LS version of the -55.