In 2005 he either was remembering things based on having heard from police that it appeared sticky or he failed to mention it at the time he testified. I tend to believe contemporaneous statements more because people not only forget things after a long period of time, they tend to incorporate things hey read or things said by others. For instance decades later one cop in another case asserted the ballistics expert identified the caliber of bullet on the scene and detectives thus knew right away what murder weapon they were looking for. This is in direct conflict with the official account. It turns out that in a book the ballistics expert said he felt he knew the caliber right off the bat. The cop took this and reported that the ballistic expert told them the caliber right away. The fine print though is that the expert said in a different part of the book that he waited until he measured the bullets at the lab to confirm he was right before telling anybody. He never told the cop in question or any other cops at the scene his suspicions.
It is not intentional revisionism but people tend to incorporate other things into their minds as time goes on. His claim he could remember the day like yesterday I don't believe one bit. Reading his statements and those of others will help him be able to recite things but I doubt he remembers every detail with specificity on his own. Back in 1985 he could not remember the exact date he found it- he simply knew it was a weekend and had to consult a calendar and be aided with the exact date from the others who were with him. That certainly calls his claim of a perfect memory into question 20 years later.
I studied memory at uni and although much of what you said is true, for big events people tend to remember the details quite well. DB seems to be trying too hard to convince the viewer, not only describing in detail but also using action to support his claim!
There are too many inconsistencies between individual statements and accounts vary between the three main witnesses, who seem unable to remember who was there and who did what. I understand that at the time they weren't supposed to know that the moderator was important, but that's NOT the way they tell it, it's like they knew from the start. RWB was supposed to have stated at the time 'the police better have that, put it in a bag' etc. David said he saw blood and paint at he scene in one statement but not in others and Ann, that it wasn't until they were around the table at the Eaton's farm. Ann said she didn't look at the silencer until they were back at her house but RWB mentions that she and DB had a good look at it at WHF.
I think if we're going to question Jeremy's inconsistencies, (and there are lots), we should also consider the same of others. I will try and list these examples at some point this week to clarify.