After scrambling to make up thousands of dollars of withholding so he wouldn’t have an unanticipated tax bill on April 15, Mike McClure wanted to see exactly how he fared under President Donald Trump’s much-debated tax reform.

The Apple Valley software salesman recently compared his tax bill for 2016 with his bill for 2018 and discovered the new Trump plan saved him $3,000.

Then, he figured out that he would lose all of that savings in two years, as soon as his two children turned 17 and no longer qualified for a tax credit.

Such are the vagaries facing middle- and upper-middle-class taxpayers with the nation’s freshly overhauled tax system.

Various estimates predicted a reduction in taxes for more than 80% of individual filers in 2018, the first year of tax reform. But how long those savings last is a more difficult calculation.

“What looks like a short-term benefit might turn out to be a tax increase,” said Matt Gardner of the Institute on Taxation and Economics (ITEP), a nonprofit, nonpartisan think tank.

McClure, for one, found that his tax depends on the age of his children.

“It’s interesting that they phase out the child tax credit at age 16,” he added. “I just paid for a high school graduation party. I will be paying for college for my two children for the next seven years. This is the time when kids are most expensive.”

The aging-out process for the child tax credit dates to the administration President Bill Clinton in the 1990s, Gardner said. What Trump did was double the size of the credit and make it available to more upper-income households.

Expanding the credit was one of many ways in which the new tax system seeks to help individual taxpayers. Lower tax rates now apply to most. Withholding rates have gone down, a fact that in 2018 caused millions of Americans to take home a little more money in each paycheck, but that also cut the number of expected tax refunds. The value of the standard deduction has roughly doubled, along with child tax credits, making it simpler for many people to file their taxes.

At the same time, personal exemptions no longer exist. Limits apply to deductions of state and local tax payments from federal tax returns. And several other kinds of deductions have disappeared.

The Internal Revenue Service recently posted information from the first 2018 returns reviewed. An IRS spokesman cautioned that the data reflects less than 90% of the returns expected to be filed. So the numbers cannot be taken as gospel. Still, the early numbers reflect some expected results.

By May 23, the IRS had paid out roughly 700,000 fewer refunds than by the same date a year ago. The number of early filers claiming itemized deductions shrank by two-thirds. The number of returns taking a child tax credit grew by 15 million. The total amount of those credits jumped from $24.6 million for early returns in the 2017 tax year to $73.3 million for the 2018 tax year. This included 1.3 million new child credit filings for people with annual incomes between $250,000 and $500,000, who were not eligible for child tax credits in the 2017 tax year.

Limiting state and local tax deductions on federal returns to $10,000 per filing drove those deductions on early filings from $282 million in the 2017 tax year down to $140 million in 2018.

Collectively, these the tax savings will have to be accounted for eventually, Gardner warned.

“All of the benefits are set to expire in 2025,” he said. “That’s the sense in which any American should be looking at it.”

The choices in 2025 will be to end the tax breaks for individuals or continue them and add to an already mounting national debt.

“Either way,” Gardner said, “things are out of balance.”