Even the president of the conservative American Action Forum, Douglas Holtz-Eakin, told the paper that while an argument could be made that the budget didn't intentionally double-count, at first glance the budget and tax-plan figures "don't seem to match".
Democrats charged that Trump's cuts would rip apart the social safety net.
But the plan does cut nearly $3.6 trillion from an array of benefit programs, domestic agencies and war spending over the coming decade - an nearly 8 percent cut - including repealing former President Barack Obama's health law, cutting Medicaid, eliminating student loan subsidies, sharply slashing food stamps, and cutting $95 billion in highway formula funding for the states.
The goal of the budget as a whole is to wipe out the annual deficit by 2027, and it calls for deep cuts in areas like healthcare and social welfare while boosting funding for defense and the Department of Veterans Affairs.
A fellow Republican is lacing into President Donald Trump's budget, saying his promises to balance it are based on fanciful economic projections.
DeVos is getting some pointed questions from Democrats on a House committee about using public money to help students pay for private school tuition. The budget does not include cuts to Medicare nor does it request a reduction of core Social Security benefits.
Pramilla Jayapal of Washington told Mulvaney that cuts to food stamps, payments to the disabled, and other programs are "astonishing and frankly immoral". Connecticut Rep. Rosa DeLauro called the budget "cruel", "heartless", "evil" and "inhumane".
But the budget does feature a major domestic initiative - a six-week paid parental leave program headed by Ivanka Trump that would be designed and financed by the states through cuts to unemployment insurance, at a projected cost of $25 billion over the next 10 years.
DeVos answered that that was not the federal government's business, but was for states and locales to decide. "I don't understand how people who are governing can disregard so many people in need", Berkowitz said.
"We believe that parents are the best equipped to make choices about education for their children", she said. "I am shocked that you could not provide one example of discrimination" that warrants federal intervention, Clark said.
Food stamp cuts would drive millions from the program, while a wave of Medicaid cuts - on top of more than $800 billion in the House-passed health care bill - could deny nursing home care to millions of elderly poor people.
Add the AHCA's $880 billion cut to the budget's $610 billion in savings, and you've got the $1.4 trillion number that's being thrown around. "Their efforts against terrorism and other disasters won't immediately collapse".
Rep. John Carter, a Texas Republican who chairs the homeland security subcommittee, says the proposed cuts of $767 million to state and local grant programs are "worrisome". He suggested that in future budgets that may not be the case.