金光明最勝王經疏 2.51

2.51

贊曰：請除疑惑，有二：初心疑、後言請。相好等同諸佛，情不生疑。壽命異彌陀等，故言唯於壽命生疑。

Commentary: Requesting the removal of doubt has two parts: first, his inner doubt; later, his verbal request. The marks and signs are equal to those of all buddhas, so no doubt arose in his mind. The lifespan is different from that of Amitābha and others, hence it says "regarding only his lifespan gave rise to doubt."