I agree. Benjamin Kilchör observes:
[T]he presupposition of a speculative historical framework can make a person blind for observations, which do not fit the presupposed framework.
Redaction criticism then serves as an instrument to immunise the proposed framework against basic criticism: whatever not fits the framework is regarded as a later redactional addition. One should therefore avoid, in my view, to be too fast at hand with datings, which are not very well justified. It is better to take a step back and look open minded to the relationship between texts and to allow for observations, which might not always fit the current presupposed frameworks.
Did H Influence D on an Early or a Late Stage of the Redaction of D?, 510 (emphasis mine).