That Walrus article is confusing as hell. I think it did a good job in that it dispelled this myth that the US just bombed the "Ho Chi Minh" trail in Cambodia, you could see from the maps that the bombing spread over much of the country. There were of course reasons for this but I don't want to get into them here. The maps all came from freely available US data.
What stood out from the Walrus article was the sudden appearance of a huge figure. Up till this time, the generally accepted figure for tonnage dropped on Cambodia by the US was around 500,000. This was the figure Shawcross used in Sideshow, his damning indictment of the (long gone by then) Nixon-Kissinger administration. Most other sources seemed to concur. Until the Walrus article came out and suddenly revised the figure to 2.7 million tons. This was again supported by figures supplied by the US defense dept.
Since then this figure has been widely quoted, but nobody seems to have noticed that the authors revised their figures a few years later and now believe the 500,000 figure was closer to the truth.
So, here's part of the redaction.
Our 2006 article, “Bombs over Cambodia,” using the same database and analysis, calculated a figure of 2.7 million tons dropped on Cambodia in 1965-75.15 Our estimate, published in the Canadian magazine The Walrus, and in 2007 in The Asia-Pacific Journal, was widely quoted.16
But in 2010 we corrected that estimate, here in The Asia-Pacific Journal. We revised it back down to around 500,000 tons.17 In doing so we took account of the mistaken technical analysis that had impacted bombing tonnage estimates for both Laos and Cambodia. Holly High had written to Kiernan on January 4, 2010: “I have been working with computer scientists here at Sydney and we have managed to make a fairly responsive database and also account for the anomalies in the data . . . The database covers all of Southeast Asia, and contains many more fields than the data that you were working with, from what I can tell from the data on the Cambodian Genocide Project website. It looks like the data you and others in the UXO business were provided with was a simplified, distilled version of the original SEADAB and CACTA files [combined Pentagon databases entitled “Records About Air Sorties Flown in Southeast Asia,” and “Combat Air Activities”], sorted country by country so that each nation received only “its” records. The original database is much larger: indeed it is simply massive. It is also deeply flawed (some of the data appears to have been corrupted and there are omissions in certain months).”
Kiernan wrote back to High on January 18, 2010 stating that “we would urgently like to incorporate corrections of mistakes that were based on faulty Pentagon data, and show where that data is inaccurate. If it is okay with you, we would of course like to credit you and your skilled research assistant at Sydney Uni’s Faculty of Information Technology, who has worked on this with you, for bringing the database errors to our attention. Obviously the sooner we correct those the better.” In an email of March 1, 2010, High asserted that in the Pentagon’s SEADAB database, the original entries for each sortie under the field of bombing “Load Weight” had been incorrectly keyed in, with a zero mistakenly added to each figure. Those bombing tonnages thus had to be divided by ten.
In June 2010, therefore, we published our downward correction of our 2006 estimate of 2.7 million tons. We stated that “this tonnage data may be incorrect. In new work using the original Air Force SEADAB and CACTA databases, Holly High and others have re-analyzed the total Cambodia tonnage figures and argue in a forthcoming article that the total tonnage dropped on Cambodia was at least 472,313 tons, or somewhat higher.” We concluded: “It remains undisputed that in 1969-73 alone, around 500,000 tons of U.S. bombs fell on Cambodia.”18
https://apjjf.org/Ben-Kiernan/4313.html