Probably a bit of both. Berkshire's size means he was limited to the largest companies which are pretty well analysed.

During that period he did some different things which some of his personal money like buying stock in Dae Han Flour Mills, a Korean flour miller that was like 2 times earnings in 2003 but was probably too small a position to make sense for Berkshire. (https://www.netnethunter.com/warren-buffett-cheap-stock-pick...)