The fact that Buffett is expanding Berkshire's position when he sees little else worth buying speaks volumes.Just when it looks like Warren Buffett is done adding a position in a particular company, you learn he isn't. Last week, Berkshire Hathaway (BRK.A -0.07%) (BRK.B 0.25%) expanded an already-massive Occidental Petroleum (OXY 1.51%) holding that hadn't been touched in months, capitalizing on the stock's 35% pullback from April's peak that more or less aligns with crude oil's price action for the same ti ...