The Tapas 9 themselves saw the timeline as crucial, making two attempts to document it. I think that was more to do with their fear of being charged with neglect than a desire to help the police. As far as they were concerned it was a fact that Madeleine was abducted and that the abductor was seen by Jane Tanner at around 9.15pm. Given that, why did they think it mattered what time others checked?
A group of people who couldn't remember anything with certainty worked very hard to convince the police that they remembered the timeline. Gerry couldn't remember which door he used, but he remembered what time he used it. It took Dianne Webster a year to remember seeing Matt, but she was absolutely sure what time Kate went to check. Matthew seemed to be describing a different apartment but he remembered what time he went there. Kate thought Russell went to check at the same time as Gerry, but she was sure what time Gerry went...and so on.
Looking at statements relating to the times before the meal began and after the alarm was raised we are in forgetful land again. What time did the men return from tennis? Between 7.10pm and 8pm. Fiona's run was never pinned down to an exact time. Gerry had no idea when or to whom he gave Madeleine's photograph and the family's passports. The other men are very vague about the times they searched or the times they came back to the apartments. Neither Kate nor Fiona are clear regarding the time the McCanns left the apartment in the morning of 4th.
The timeline should have been examined at the time, but Amaral's superior (Encarnacao?) apparently blocked it. In my opinion the timeline is the result of agreement by a group of people with a vested interest in producing proof that their children were adequately cared for. It has not been independently verified by anyone outside the interested parties and therefore can't be relied on.
Giving this a quick thinkover, who could provide such independent verification?
Until Madeleine disappeared, it was a non-memorable evening.
The waiters clearly hadn't a clue who was getting up and when, and they had no particular reason to.
I don't know how many other diners were in the Tapas that night, but why should any of them remember?
And I can't think of anyone outside who would take notice of this.
If some or all of the T9 have tweaked the time line, they have done Madeleine a grave disservice. We have no actual evidence of tweaking, merely that agreeing a time line seemed to be high priority.
And of course they actually produced 3, 2 on the child's book and a 3rd by computer.
That I find very strange. I would know when I went. I would know when my partner went. If a 3rd party checked my children, I would know when that happened. But even if the people sitting next to me went to check other than my children, I wouldn't remember, unless the checks were not time-driven but event driven e.g. person X got up between starters and main and that would be about ... while person Y got up after finishing the main course, and that would be about ...
The desire to bash out an agreed time line is very odd, IMO.