The 25 minute delay is probably because he was on the phone to Jon Corner for 24 minutes from 19.10. (see comments)
See Dr. Robert's analysis in the comments: Paiva never used the word 'buried'.
(Processo: VOL ,X, p. 2587-2602)
This fact became inexplicable to the elements of the investigation once it were the members of the family that raised the hypothesis of death of little Maddie.
Nevertheless, before the Media they kept (and keep) declaring their hope on finding their daughter alive: the first time that the hypothesis of the death of the little girl was raised it was, effectively, suggested by the McCann.