Of course, nobody can calculate with precision, but if two companies have a significant difference in undervaluation, it may be advantageous to bet more on one than the other. The difference may not be so obvious between your best and second best ideas, but perhaps between your best and sixth best ideas.
This is the point I'm making. I'm a believer in concentrating, but one stock seems to go too far in my opinion. I think there's a reason Charlie Munger says 3-4 stocks is enough but never quite goes so far as to say you only need a one stock portfolio. Concentrating on your best few ideas makes a lot of sense. If you think something is a 2.5-3.5x, and you think something else is a 2-3x, it's hard to say which one is truly "better" on its own, you should probably own both. Sure if you have one amazing idea thats a 5x and your next best idea has 20% upside it makes sense to concentrate on only your best idea. But practically speaking, you won't find yourself in that position. Comparing your best idea to your sixth best you might find yourself there.
The point I'm making is that it's true that over the long run, on average, the larger the discount to intrinsic value, the better your idea will perform. But if you are making so few bets (one every year or two), you don't get the luxury of thinking about averages because your sample size will be so small.