I had power cal errors on this same unit about 3 months ago, using only verb +R DL and imgbrn. (BTW: SL worked fine) Several DL disc's later and a suggested fix from Liteon, which didn't work, I RMA'd back to newegg. They even paid return shipping. Got credit and bought the 20A4 and continued to burn from same spindle of verb DL with no issue.

Regards