It depends a lot on the tester and the individual child. Typically, it takes high functioning children longer to finish (longer to trigger the discontinue rule). With very young children, the way some testers maintain rapport and optimal attention also can result in many short sessions.
I don't think her multiple sessions were a function of III vs IV (nor do I have any reason to suspect it was fake!). It's probably just the combination of the tester's willingness to let her chat, and the chattiness of your DD.
