The really incredible thing about Bill's research is exactly that - his painstaking research. Without pivot tables, it can be exceedingly difficult to find a credit of "O" (capital letter O) in an enormous column of "0s" (the number zero). While you can maybe find the odd error, pivot tables merely focus the search in the right area. I forget exactly what he found, but it was 100% Bill's data. His research of Report 85 goes way beyond anything I have ever seen before, but I have noted that many government reports and summary tables from the post-war but before personal computer days have math errors in them.
The errors are not usually major, but are generally off by a couple from the tabular data they are supposed to summarize. Also, many government reports have been transcribed using OCR software and the early OCR packages would sometimes make the strangest errors. I have found victory totals with "III" (3 i's) where a "3" should go, and that makes no sense from an OCR perspective. Several records in report 85 have letters where victory credit numbers should be. When I tried to look them up, the ones I could find and confirm suggested a systematic OCR error. I think it was likely related to the fact that the report was generated on a dot-matrix printer, and the OCR software was sometimes having a hiccup on some specific dot matrix pattern.
Bill's data, on the other hand, seemed to contain only ONE error in the entire data set of more than 15,000 records and I can't recall exactly what it was. But he zoomed in on it rapidly. His work definitely outshines the collective efforts of specific government studies I have managed to look at in some detail, accuracy-wise. If you want a very good, accurate look at some ETO data, his work is a premier place to start. I trust his numbers more than any other source I have found to date.
Now if we can just get him to look at the rest of the theaters and publish, we'll have some great data, at least for the USA. Who knows, maybe he speaks German, Japanese, AND Russian.