When various journalists have volunteered to get taped getting the waterboard, we count that as ONE because not one that I've seen has lasted more than a few seconds, and I've seen no one have that repeated. It's the same way the 183 was counted.
How should it be counted? Let's say you're on the receiving end, the water was poured over your face, you're unable to breath, ingest a bunch of water, choke, gag, vomit, before they quit pouring, and then they let you rest for a few minutes before doing it again. It would make a helluva lot of difference whether that "application" happened once that day or 40 times. Apparently, the right wing apologists want to count 1 "application" and 40 as equivalent, and just count it as one "waterboard." Which number better reflects what happened? One or 40? If it was you, I can promise it's 40.
BTW, the report is extensively documented with hundreds or thousands of footnotes. Every important statement is supported by an original document. It's legitimate journalism to quote from that kind of document - that's what journalists DO. And as many have pointed out, I've seen almost no allegations that any facts cited in the report are false. And if they're false, then the underlying documents contemporaneously prepared by CIA or other officials and cited in the report were false.