The adjustment period will take a bit of time (up to two weeks) for a four month old, so be patient with the transition time. Pay attention to your baby... if you think she's hungry then feed her at her night waking. If you get her back to sleep and she is waking in a short time, then maybe she was hungry. Also, if she takes a full feed and then goes back to sleep without much fight then she was probably hungry. When she learns independent sleep, you will be better able to tell if she is waking out of hunger or just for a visit from you. Tracey's book recommends doing the PU/PD routine at this age as opposed to shhh/pat, so your instinct might be correct that the shhh/pat is becoming a prop.