When Fort Worth school trustees last year were asked to freeze an expensive retirement bonus program to contain costs, one argument against the proposal was that employees needed time to adjust to getting smaller checks than they were expecting.It was a weak argument. So were most of the other reasons cited by the board majority that postponed the fiscally responsible -- if difficult -- choice to revise the program known as terminal pay.But the issue returns Tuesday night. And it's just as imperative now for the board to get this long-term liability under better control.Terminal pay is a longevity incentive that appears to have started with good intentions when teacher salaries were woefully low, but it has worn out its justification. And given the perilous condition of school funding, allowing this perk to keep growing just isn't affordable.Chief Financial Officer Hank Johnson said that if the employee bonuses are frozen at their calculation as of Aug. 31, the district would have to pay a bit more than $47 million over the next 13 years as workers become eligible to retire. If trustees don't act, "the costs per year will creep up rapidly," he said.Terminal pay is added to an employee's final paycheck upon retirement, based on ending salary and years of full-time service. The salary is divided by 183 to get a daily rate. The bonus is determined by multiplying the daily rate by years employed (only years with a satisfactory performance review) then adding unused sick days up to 20.Freezing the bonus wouldn't deprive any eligible worker of what they otherwise would have received for service to date.It wouldn't affect anyone's salary or state retirement payout.It simply would mean that whatever bonanza eligible employees would get if they retired this year will be what they receive no matter how long they stay.Only those hired before Aug. 31, 2003, can receive terminal pay provided they meet other retirement criteria.That means 4,896 of the district's 10,129 teachers, administrators and other staffers would be affected by a shift in policy. (About 500 terminal pay-eligible employees retired last year.)No one stands to receive as much as Superintendent Walter Dansby, whose estimated bonus was $85,573 before trustees raised his salary from $270,000 to $328,950 upon naming him to the top job earlier this month.Other top terminal pay estimates provided by the district in response to an Editorial Board request include Associate Superintendent Sherry Breed at $39,648; Chief of Schools Robert Ray at $37,815; and Early Childhood Director Patricia Rangel, wife of school board Vice President Juan Rangel, at $28,492. All have 20 or more years with the district as of 2011-12.The board's decision shouldn't rest on who is eligible or how much anyone might receive, but on what's best for students in the district and residents who pay the bills.The district already anticipates a $55 million budget shortfall. To avoid layoffs, officials have moved to shed jobs by offering cash incentives to up to 700 workers who give early notice of their plans to retire this year.Trimming costs never is easy. But making systemic changes like freezing a nonessential subsidy involves far less pain than cutting into the heart of what happens in classrooms.