Firstly I would apply that many things were skewed somewhat when working around the many lies from Lean; Such as saying SM was off out around 5:30pm, wouldn't do for the truth here because his actual time of leaving fits around his younger brothers actions that evening. SM was home until at least 6:20pm. But let's just look at what I have always said.
There are no sightings of Mitchell from where he claimed to have been. He had been seen by boys who knew him, he applied he had walked to BC and back again a 'couple of times' because he had been seen, and again by one of the boys on his return journey. It is not the same thing at all as being seen where he claimed, it is the other way around. Giving reason for being seen there those two times, where he could not dispute being identified. In a small time frame he was seen by them and two motorists. It doesn't matter if he was seen 20/30mins later by the boy on his return, it is the same thing. A brief sighting that he incorporated in his claim of walking there and back to where he was never seen.
He was seen several hundred yards away at the point where he claimed to be sitting on the wall around the bus stop. Seen by F&W near to RDP and the woodland strip where Jodi was murdered. And some 45mins before then by AB in Easthouses.
The shuffling around those lies. SM didn't leave home until after 6:20pm and not around 5:30pm. I would imagine that dealing with his mother would be one thing after such an event, dealing with his brother something else entirely? What took place between then and his second call to DH? He had asked him to his house, 20mins barely passed by and he chases him, but he doesn't just chase him to see where he was as always thought, he called him to change the meeting place away from his house and in the Abbey instead. At that point a fire had been decided upon in the Mitchell garden. If he did have a phone in view when the boy on the cycle past, we can certainly apply this may have been his first call to DH. Let's face it, the second call to his mother, the reason they gave was absolute nonsense. The claim of asking if Jodi had been to the house.
Therefore it all still stands. Being seen collectively in a short period of time, then briefly some time later does not equate to Mitchell being where he claimed, does not equate to him standing out on NR in full view of everyone for that ludicrous time frame, not even close.