WOPC in the Benq also governs important parts of the write strategies. In fact, some of the write strateties turn off WOPC. Personally, I would not want to manually override the WOPC setting for a disc that relies on it for the write strategy to work correctly. No way! Heck no! Leave WOPC turned on! (for me).
I actually use and rely on my BenQ 1620. Now, if it were just a toy, I could understand fiddling with the WOPC. Since I want my discs to actually play back on a set-top player, I need that WOPC to do its job of insuring good play-ability of the written disc.