It depends a bit on your claim basis for application - academic or experience. We brought all our accountant letters for our companies, and other bank items, (with photocopies), and handed them in at interview, as they were relevant to our experience.
However I think they only glanced at the top of the piles, and flipped through. They handed back one IRS item to us - can't remember what it was but they didn't need it.
If you were applying on basics of only academics then it is unlikely they would need to go that far with your experience, unless doubt existed. As has been mentioned in an earlier post by
@Britsimon - KISS - keep it super simple - make it easy for the staff to tick the check boxes - (keep what you don't need separate, but just in case you are asked you can produce it).
Interestingly, with wife as PA (DV1) , I didn't expect to have my (DV2) academics checked, but they did. I think the basis was that ? do these applicants not just have the experience to do what they say they can do, but also the academics behind the experience. But I think in an OC pool / consulate group we were probably more exceptions to the rule, based on the brevity of interviews everyone posts. ... Stick to KISS.