Rock-a-bye and good night, go to sleep my dear Adia

Lately Adia has been giving us a hard time when it's "nighty night" time. Despite the usual sleep routine that we've been doing for the past eight or so months. Normally after a late feeding of veggies and cereal we play, get changed and into jammies, nurse, snuggle and off to bed. Rasa is usually out after Royce gives her a bear hug in the rocking chair for five or ten minutes and then Adia is next. Lately Adia sees Royce walking to her and she smiles and lets him pick her up but the second he walks her down the hallway towards her room she starts screaming! When he turns around and she sees me she smiles and laughs! Now normally I would say too bad if she's screaming in this case because she obviously knows that it's going to get her out of having to go to bed but Rasa is peacefully sleeping in their room and it's not fair to allow Adia to disrupt her and wake her up. We know very well that allowing this to continue will likely cause her to expect that this is how she gets out of having to go to sleep when she should HOWEVER (enter Mom guilt here) I have a slight suspicion that maybe she likes the one on one time with both of us and she's not willing to give it up? I mean she is a twin after all and never gets very much time alone with BOTH of us. Or possibly she's having too much fun to want to go to bed? Last night we were reading and I was showing her the signs for the animals in a book. She was having a blast signing after me and was beside herself with excitement over the sign for fish. She kept turning the book back to the fish page, smiling and signing it with both hands at the same time. When Royce went to take her away she was crying and reaching for me while signing fish. How could I let her go?!! I'm weak. She ended up back on my lap until after 10:30 pm until finally her lids were so heavy she didn't mind me handing her back to her Dad and while she did try and protest once he got her in her room it was a tired attempt and she was out two minutes later.
**sigh** Six months of hard work to get them on the same routine only to have it all squashed by fish.