DVD+DL discs not being recognized by other burner drive

[qanda]This thread is about the Lite-On LH-20A1H. Click here to see full specs[/qanda]In September of 2007, I bought a Lite-On LH-20A1H off of Newegg & installed in in my 2002 Quicksilver Mac. All was well & it’s been cheerily working well for me. However, because my desktop mac only has an 800 MHz processor, it’s super slow in encoding & burning, often taking 10 hours for a DVD.

Eventually I ended up getting a late 2006 13.3-inch Macbook laptop to supplement my computing capabilities. I quickly upgraded the hard & optical drives on the laptop to meet my needs; in the case of the optical drive, it was swapping out the factory-installed ComboDrive for a GSA-S10N. This would enable me to burn the discs I wanted in less time.

Although I’ve had the unit configured like this since early April, I hadn’t really had the chance to really start burning things until the other night. I did a couple test discs & found an interesting & annoying snag: the DVD+DLs (Memorex 8x discs) that I burned on the GSA-S10N will not be read or even acknowledged by the Lite-On drive.

At first I thought there might be a software issue, so I reinstalled Toast 9 Titanium & tried again. Same deal. Today before I went to work, I stopped by the Office Depot near my workplace & tested both burned discs on one of the random Windows laptops they had on display there; both discs performed perfectly.

My question, then, is what could possibly be causing this problem with the Lite-On drive that it refuses to recognize the GSA-burned discs? Might something have flipped or tweaked? Might it be a simple incompatibility? Is the drive lapsed into obsolescence? Does it most like need to be replaced, & if so, should I bother with another Lite-On drive, or should I look for something else…perhaps something Mac-specific? (Finding drives that mention Mac use in their specs is akin to finding a virgin on the streets of Vegas)

I look forward to the responses.