This is a copy of a post I put up on the Adobe forums
I built my project to the VIDEO_TS folder on my hard drive a few days ago with CS3. I then imported it into GPME (GEAR Pro Mastering Edition) only to discover that the layer break that Encore had set would only leave a few megabytes for layer1 which is obviously way way wrong (4,124,896 sectors is what was detected in GMPE for the layer break!). Neil informed me that I should write the master directly to DLT from Encore because it does it correctly whereas it writes junk into the files if you do anything other than mastering to DLT.
NOTE: I DID NOT RE-TRANSCODE ANYTHING. In the area for the layer break options, the "If Possible, Use Existing Layer Break" was checked AND it was greyed out so I couldn't unselect it so I just proceeded.
Well, in an effort to check that the layer break was correct in the DLTs that Encore wrote, I restored the DLT tapes to the hard drive using GPME's guide and then mounted the image to a virtual drive. I created a new project in GPME and imported the VIDEO_TS only to discover that it detected the same layer break as it did when I wrote the VIDEO_TS files to the hard drive a few days ago.
The only possible reason I can come up with for this is that it is necessary to revert the assets back to original before disc build in order to get a new and hopefully correct layer break? Can someone confirm this? It doesn't make sense because I'm fairly certain that the layer break info is contained in the IFO files which are not created until disc build so transcoding again doesn't seem logical, but maybe I'm wrong.