I have a NEC 3550a and tried it with different types of media, including verbatim +R DL.
All i have so far is 7 coasters. Even tried to upgrade the firmaware of my burner to 1.06y. No luck.
Then i tried the other burner a NEC 3540a. Also no succes.
I think NEC just wont work with backups, so maybe it time to go out and buy a pioneer 111d.
Or wait till they bring out a good crossflash for the NEC which burns a better Lead-in.
for now NEC = FAILURE