Don't know, and would love to hear from someone who actually does know.
From what I have read elsewhere, "it depends" - in some systems, they only get an aggregate total. In other systems, if they want to bother looking, they can see every individual item. I do not have any direct knowledge of these systems, but that's what I've been told from multiple sources. It would not surprise me if they could see details.
Of course, we have no way of knowing which systems allow the detail view (assuming it's true) and which don't. I always assume they can see everything, so I try not to give them a reason to bother looking.
In any case, I think that if you make regular purchases that always total exactly $1007.90 (to pick your example), it's providing an obvious trigger for some algorithm. It can't hurt to throw in something small to randomize and vary the number.
Ultimately this is just speculation, but it seems like a prudent practice to me (now if I just knew what to do with all those damn slim-jims I've been collecting at the beanery....).