Repetition in the second line is deliberate. Legge's translation again shows its subject advancing in company with the line below, promises good fortune, and adds that advancing will be in every way advantageous, the strongest unqualified statement anywhere in this hexagram. Where the first line had a condition attached, the second has none, and the Little Symbolism supplies a curious reason: the subject does not yet entirely follow the commands of the fifth line above.
That remark is easily read as criticism and is better read as description. A strong stroke occupies the second, even place, incorrect by the standard rule but central in the lower trigram Dui, and its correspondence runs to the yielding ruler in the fifth place. Independence of judgment at this station is what a soft ruler above actually needs from a strong line below, since such a ruler governs by drawing capable help rather than by issuing instructions to be executed to the letter.
The pairing with the first line matters as much as the difference. Both strong lines advance together into the four yielding lines above, and the second carries the movement's centre. Its freedom from qualification is the hexagram's high point of confidence, placed early, before the third line shows what the same advance looks like once substance has dropped out of it.