LITE_On won\'t burn disk-at-once (Lite-On SHW-160P6S )

[qanda]This thread is about the Lite-On SHW-160P6S. Click here to see full specs[/qanda]My 2-yr old Lite-On SHW-160P6S has stopped burning disks-at-once. I make backup copies of all my movies. The problem was at first occasional and I could get around it with Nero recode, but now it occurs every time I get to the burn stage – with any burning program. I still can burn tracks with no problem.

My firmware is the latest.

I’ve not heard of a burner losing only 1 capability – the burn-at-once – and having the others remain functional, but it can happen I guess. The s/w I’m using is Nero and 1clickdvdcopy.

Anyone else see this before? I’ve bought an Optiarc AD7200A as a replacement, but before I uncable and pull apart my system I want to check that this kind of problem is possible.
Thanks for any help.