We are 80+ years on, so I think the story is well understood.

The only thing I can think of would be that all the first-person descriptions were aweful and probably overlapped. By that I mean that every survivior described terrible scenes--the same individual scenes were probably described multiple times and in different ways.

Example--a soldier's intestines are out and he is screaming in pain. If this guy was seen by ten fellow sodiers, it was probably mentioned in ten different histories. As readers, we can err in thinking that ten different dudes were lying on the beach with their guts hanging out (there were probably ten or more examples, actually, but there are probably dozens of stories about such scenes).

But in the end, we have a good idea of how many died and were wounded. We have testimonies from German gunners who describe the scene as horrific. We know certain units were basically eliminated entirely--they just disappeared.