Ford and the UAW revised the tentative deal that workers are currently voting on, giving in-progress workers a bigger-than-expected raise.

Some 10,000 UAW workers voting on a tentative contract with Ford Motor Co. will get a bigger raise than expected if the deal is approved. Voting is scheduled to end Nov. 15.

The two sides revised a section of the proposed deal that could cost the automaker an additional $15 million during the life of the four-year agreement, according to the Detroit Free Press. The move came to resolve a calendar issue.

“It was a glitch,” said a person with knowledge of the situation not authorized to discuss the matter told the newspaper. “This just shows the commitment of the company to work with the union to make sure that this agreement is what it was meant to be for all the employees.”

(Workers at Chicago Ford plant vote down proposed deal)

The changed to the contract permits the union to synchronize the worker pay raise schedule. This means that newer workers who already received their annual pay raises get retroactive pay to catch up to the new contract’s improved pay scale that would take effect upon ratification Nov. 15.

UAW and Ford executives gathered at Ford World Headquarters to begin negotiations for the 2019 contract.

According to a UAW memo distributed at Ford plants titled, “In-progression wage transition disparity issue has been fixed!” the change prevented the unintentional penalizing of workers with an employment anniversary date prior to scheduled ratification, the Freep reported.

The move to make the change in the language signifies a shift in the relationship between the two sides, according to Harley Shaiken, a professor at the University of California, Berkeley, who is considered an expert on labor affairs, particularly the UAW.

(UAW Ford Council endorses tentative agreement)

“I think it is a rare, if not unprecedented, development. It corrects and obvious error and clearly benefits the workers,” he told the Free Press, adding the speed of the correction “reflects the relationship between the company and the union. It means that they discovered an error and rather than let it slide they sought to correct it.”

Ford’s large plant in Chicago has voted down the tentative agreement between the automaker and UAW. Other large plants are indicating they’ll do the same.

The vote on the contract is expected to be tight, and hit a speed bump as workers at the company’s big Chicago assembly plant voted to reject it by a decisive margin.

The unofficial tally from the vote by both production workers and skilled trades had 1,599 union members voting no while 1,030 voted yes. The breakout had skilled trades voting to accept the agreement 117 to 102 but production workers voted it down 1,497 to 913.

(Ford, UAW Reach a Deal That May Include $6 Billion in New Investment)

Meanwhile, local leaders from UAW Local 249 at Ford’s assembly plant in Kansas City, Missouri, have indicated they do not intend to support the tentative agreement after speaking out against it during a meeting for the UAW-Ford Council in Detroit.