The patristic allegorical school: every detail signifies: Augustine reads the Good Samaritan with the inn as the church and the two pence as the two commandments of love (Quaestiones Evangeliorum 2.19, PD).
Its strength: Jesus himself interprets the Sower and the Tares point by point (Matthew 13:18–23, 36–43). The one-point school: a parable makes a single point of comparison and allegorizing details is eisegesis (Jülicher, Die Gleichnisreden Jesu, 1888–99, cite; Dodd 1935 and Jeremias 1947 added kingdom-eschatology and the Palestinian setting, cite-only). The modern middle: one point per main character, with Jesus' own practice licensing limited allegory (Blomberg, Interpreting the Parables, 1990; Snodgrass, Stories with Intent, 2008, both cite-only).
All three presented at strength; the recorded interpretations of the Sower, Tares, and Dragnet are displayed as the data every method must satisfy.
Older commentary reads Jesus' own paired interpretations as a single design, not two isolated explanations: "Here are two parables intended to show that there would be a mixture of good and bad in the gospel church, which would continue till the great separation between them in the judgment day." — Matthew Henry, Commentary on the Whole Bible (1710), on Matt 13:18–23. The full chapter sits inside the book hub at Matthew. Sources: parables brief §5; Augustine PD; moderns cite-only.