Elon Musk’s Department of Government Efficiency has deleted hundreds more claims from its mistake-plagued “wall of receipts,” erasing $4 billion in additional savings that the group said it had made for U.S. taxpayers.

Late Sunday night, the group erased or altered more than 1,000 contracts it had claimed to cancel, representing more than 40 percent of all the contracts listed on its site last week. The deleted items included five of the seven largest savings that it had claimed credit for just last week. At the same time, the group added about 1,000 additional canceled contracts, worth smaller total savings.

It was the second time in a week that DOGE had deleted some of its greatest claims of success. Early last week, it erased all five of the largest savings it had claimed when the wall of receipts, which is what the group is calling its list of canceled contracts, was originally posted on Feb. 19.

Since that first posting, the total amount of savings that the initiative has claimed from cutting contracts has steadily declined, from $16 billion at first to less than $9 billion now.

The “wall” shows only some of the cuts Mr. Musk has imposed on government, making it difficult to assess the claim that his initiative has saved taxpayers more than $100 billion. But the site is the only place where the group has given a detailed public accounting of its work, providing a rare look at its basic competence and familiarity with government data.

Contracting and budget experts say that look has been worrisome.

From its start, the list has been full of errors: claims that confused billions with millions, triple-counted the same cancellation, or claimed credit for contracts that had ended years or even decades before. Contracting experts said these mistakes raised questions about DOGE’s basic understanding of the federal government, at a time when Mr. Musk’s group is attempting to rapidly overhaul it.