Good catch on the March 7, 1998 issue. At that time he switched Microsoft and Vodaphone to 4% based on market value, while leaving other stocks on a cost basis.
I notice that in that issue he also mentioned the entry point on MSFT as a split-adjusted $4 in 1990. There have been two 2:1 splits since March of 1998, so that means the entry point was at a split-adjusted $1 per share in today's terms. Apparently he forgot about one of the splits when he said $2 this weekend.