Allegro can be interpreted in many different ways. Sometimes, this tempo marking can be misleading because it is sometimes used as a generic name for the first movement of a sonata, like Mozart. Andante being a generic name for the slow movement.I ignore these types of markings because it does not mean much as to the interpretation of a piece; I interpret the notes, not the words. If you interpret the notes, you'll understand the piece better than if you read just the words.