I still think CW has feelings for Anne which he cannot overcome at this point. If he found the situation with Anne truly awkward or she was making him as uncomfortable as he was making her, wouldn't he just leave Kellynch to visit his brother? He could always come back to Kellynch and resume his pursuit of the Musgrove girls after Anne had left for Bath. He has the option to leave; Anne doesn't.

(Then again he never speaks to her so maybe he does not know of her plans for Bath, though I would think others would have informed him.)

I read that quote as starting with the ON, but then subtlely shifting to how Anne was explaining to herself his continued presence. She must be wondering why he was still around tormenting her? That is why she had herself convinced he had no feelings whatsoever left for her and was there to enjoy the company of the Musgroves. I think that only when his actions (rescuing her from the naughty child and lifting her into the carriage) started to contradict his cold words, did Anne begin to think of the possibility that maybe, just maybe, he could still be feeling some warmth towards her.