A very simple and effective plan. We could do the same thing Smithman accomplished in a reconstruction. Madeleine is moved out when everyone is at the table. So how do they know she has left? They don't, they can't see nothing - they only presume she's in the apartment. After the alarm is raised she is moved a second time unsuspected by the others who are preoccupied with trying to find her but Smithman is the only one who knows where she really is. SY/PJ will discover that this is what happened to Madeleine and how Smithman fooled everyone.
I suppose it is possible that there was an attempt to move Madeleine at around 9.15pm, which is when some of the eye-witnesses report hearing a commotion. This might have been thwarted, or the plan changed for whatever reason - Jeremy walking around for instance.
Jane Tanner was conveniently in her apartment or out an about at several key times that evening - 9.15pm (is) when she claims she saw Gerry talking to Jeremy and again at 10pm when she said she was in her apartment and heard a commotion. Jane claims she saw Jeremy but as far as I am aware in his witness statement he says he did not see her when he was talking to Gerry.
If there had been an earlier attempt to move Madeleine at 9.15pm (ish) which had been thwarted or changed, for whatever reason (and Jane Tanner seems to have been all eyes around the resort that evening - here, there and everywhere!) then that would account for the timeline in Kate's book being different. The Matt 'check' was added and then Kate's final 'check' was given to coincide with a later 'abduction' time.