It totally depends on the table. For example, there's little question that the bigger the difference in postflop skill level between you and your opponents, the more hands you should play (assuming the difference runs in your favor, obviously).

Since the players tend to be better at higher limits, your advantage is reduced, meaning that you need to tighten up. So my guess is that if we ran the same searches at higher and higher limits there'd be fewer and fewer successful LAGs(although the few that are successful might well be more successful than the TAGs).