DES MOINES — Iowans could see an estimated $1.538 billion cut in their individual federal income payments in tax year 2018, but the changes could mean they pay an extra $260 million over three years in higher state taxes due to Iowa’s federal deductibility law, according to a state report released Friday.Director Courtney Kay-Decker and analyst Amy Harris of the Iowa Department of Revenue said their preliminary analysis of the federal tax reforms passed by Congress and signed by President Donald Trump last month would reduce overall income tax liabilities for 1,440,402 Iowa taxpayers by more than $1.538 billion.The cuts would range from an average of:• $186 for those making $20,000 or less, a 155 percent reduction, for 431,285 Iowa taxpayers.• $639 for those making between $20,001 and $40,000, a 49 percent reduction for 325,496 taxpayers.• $1,076 for those making between $40,001 and $80,000, a 20 percent reduction for the 354,375 Iowans.