Interesting quote from Adam Kamesar's chapter on "Biblical Interpretation in Philo." Here is dealing with that fairly unique characteristic of Philo, namely, that he accepted both literal and allegorical interpretations:
"As Augustine would put it later, one must recognize as figurative 'any passage in divine Scripture which cannot refer, in its literal sense, to ethical rectitude or to doctrinal truth' (Christian Doctrine 3.10.14). Philo does not make this criterion as explicit as Augustine does, but he seems to implicitly follow it... He also indicates... that if one follows the allegorical method, one will never find anything 'low or unworthy of the greatness' of the Scriptures. The assumptions that underlie these directives are well expressed in 2 Timothy 3:16, a passage which no doubt reflects Judeo-Hellenistic thinking: 'All Scripture is inspired by God and is beneficial (ophelimos) for teaching, for reproof, for correction and for training in righteousness.' It is the notions expressed in this verse that explain the need to interpret allegorically passages that are acceptable in their literal sense" (80-81 in The Cambridge Companion to Philo).
In other words, some passages may need to be interpreted beyond the literal meaning in order for them to have instructive import.