Sound qiyas is analogy supported by a valid original case, governing rule, effective cause and parallel new case. Here it assists interpretation or preference among plausible readings of Sunnah reports. It does not authorize a jurist to discard both reports and invent a contrary rule.
Where reports admit more than one possible application, a well-supported legal principle may strengthen one interpretation. The principle itself must be relevant and legally sound.
Distinction: deriving a new rule by analogy in the absence of governing evidence and employing analogy as an interpretive aid are not the same operation.