The FIDE rating regulations say:
8.5 Determining the rating change for a rated player
8.51 For each game played against a rated player, determine the difference in rating between the player and his opponent, D. [...]
8.54 A difference in rating of more than 400 points shall be counted for rating purposes as though it were a difference of 400 points.
8.55 (a) Use table 8.1(b) to determine the player’s score probability PD [...]
But table 8.1b (which seems to be used only for this purpose) contains entries that go higher than 400. What use are those entries? Why are they there in the first place if they cannot be used?