Inkigayo PD's Interview about Big Bang can be seen below.
Inkigayo PD: Bigbang had last recording a few days ago, they has worked really hard. They recorded 2 songs per week for 8 weeks, they worked very hard. Well there are some people who reached that level like Bigbang, they stopped trying. We should record several times to catch good one, they never grimaced. Never. They worked very hard whenever they recorded. Actually, some singers who became popular are pretentious and they forgot their original intention. But Bigbang is different from them.
Source: sbs via forever-gdragon