Glad to here you’re not multi tasking while burning.
I too have the Liteon 812S, you may already know this but you can convert this burner to a 832S that does dual layering merely by changing the firmware.
I have not done it to mine yet because at 15.00 a pop, for dual layer disks, it makes no sense to buy them.
Information on this can be found at the CDFreaks Liteon forum, look for the Omni Patcher thread and read what it can do. It also provides a link for you to download the firmware. You will need the stock 832S firmware version VSOA to flash the 812S so it becomes a 832S. No harm done if you don’t like the performance, you can always re-flash and go back to the 812S firmware you now have.