The difference between 277/1 and 277/2 seems quite subtle to me, but the McCann team said that the use of 277/1 was correct because the investigation had gathered enough evidence to prove the arguidos innocent.
"As far as the appellants are aware of, the archiving at stake was carried out, in the course of the investigation, because sufficient proof had been gathered that the then arguidos did not commit any facts of a criminal relevance and in any way whatsoever, this conclusion substantiating an archiving for factual reasons"
http://www.gerrymccannsblogs.co.uk/Annulment_request.htmThey are ignoring, however the quite clear statement in the document that;
"We believe that the main damage was caused to the McCann arguidos, who lost the possibility to prove what they have protested since they were constituted arguidos: their innocence towards the fateful event; the investigation was also disturbed, because said facts remain unclarified."
So their innocence wasn't proved at all, according to that paragraph, and that's one of the reasons why the SC judges corrected the archiving dispatch to 277/2; insufficient evidence.
In support of the SC judges, it was mostly in the UK that the archiving procedure was reported as having cleared the arguidos. In Portugal it was reported correctly from the beginning as being due to insufficient evidence.
Portugal's attorney general, Fernando José Pinto Monteiro, said there was insufficient evidence to continue the police case.
https://www.theguardian.com/uk/2008/jul/21/madeleinemccann.internationalcrime