In chapter 4 Anne was persuaded she would have been happier to maintain the engagement than give it up; she seems to be identifying a decided preference for maintaining the engagement and this happiness would have occurred in spit of the "disapprobation at home". The disapprobation would surely have included anything Lady Russell could have said against it. This does contrast markedly with Anne's later comments in chapter 23 where she would have suffered in her conscience had the engagement continued.

I can only suggest the comments in chapter 23 were a diplomatic way of bringing Lady Russell and CW together, since the comments in chapter 23 are directed towards CW.