The state of Kansas is urging the state's high court to avoid granting a "heckler's veto" to a school group that says lawmakers shortchanged students by hundreds of millions of dollars in annual aid when they calculated an inflation correction for the K-12 education formula.

In documents filed Monday with the Kansas Supreme Court, the Kansas Attorney General's office says the addition of $90 million in annual funding should satisfy concerns raised by the court with last year's plan to phase in a $522 million increase over five years.

Attorneys for the state say in their brief that Schools for Fair Funding is alone in its opposition to legislation passed earlier this month.

"Just because some plaintiff districts will always want more money, they should not be allowed to single-handedly override the governor's and Legislature's reasonable and considered funding determinations," the state said.

The two sides are staking out territory ahead of May 9 arguments, when supreme court justices will have to evaluate a series of mathematical gymnastics conducted by lawmakers hoping to satisfy a constitutional responsibility to adequately fund public schools.

A Senate-led bipartisan effort produced a plan based on recommendations from the state board of education and Democratic Gov. Laura Kelly, who asked the court on Monday for permission to file a supporting brief. Schools for Fair Funding initially endorsed the plan, then withdrew support after closer examination of how new money was factored into the formula.

Last year, the high court provided tentative approval for a plan to pump $522 million into public school funding by the 2022-2023 school year. The legislation was an attempt to re-embrace funding levels approved in a 2006 settlement with schools, but the court pointed out that lawmakers failed to account for inflation beyond 2016.

To assist in efforts to fix the plan, the court suggested an annual increase of 1.44 percent would suffice. The state and schools disagree on whether inflation should have an accumulative effect.

If 1.44 percent were added to aid every year through 2022-2023, the state would need to pay about $360 million on top of the $522 million in new money. Instead, lawmakers divided the $360 million into four payments.

In other words, the two sides are about $270 million apart on where spending should be by 2023, when a provision built into law would adjust funding in line with changes in the regional consumer price index.

"This court," the state said, "is not in a position to resolve disputes about the proper method for calculating inflation. By relying on the Department of Education's inflation calculation, approved by the state board and the governor, the state has met its burden."

Mark Tallman, of the Kansas Association of School Boards, said the math favors Schools for Fair Funding, but the court could accept the state's argument for several reasons. The high court has relied on the expertise of the state board in the past, Tallman said, and justices may give some latitude for making a good-faith effort and being "close enough."

"This was never precise," Tallman said. "The method used last year was kind of a guess to begin with."

The court also could order lawmakers to make further corrections next year.

This year's inflation fix was adopted over concerns by some House Republicans who wanted to eliminate $200 million from last year's plan and redirect money from base aid into policy-based initiatives. Lawmakers passed the plan shortly before adjourning for a three-week break, allowing just 11 days for attorneys to meet Monday's deadline for written briefs in the case.

"All litigation — even school finance litigation — must eventually end," the state said. "In Kansas, that time has come."

The two sides have until April 25 to respond to initial filings. After oral arguments, the court schedule calls for a ruling by June 30.