Mrs. Allen along with characters such as Mrs. Bennet and Mrs. Dashwood are all wishy washy but their reversals don't seem to be of the moment, saying/doing one thing in one breath and another in the next. Their reversals seem to be, as far as I can recall, after they are proven to have done or thought something wrong and then conveniently forget it acquitting themselves of any responsibility: 'Wickham/Willoughby is great', becomes after they've been exposed to be the villainous instead---'I always knew he wasn't to be trusted', that sort of thing. I don't recall that their everyday conversations are filled with duplicity. Please note, this is not a well thought out answer but kind of off the top of my head so...