Just when Mayor Nutter thought his tiffs with unions were over, a $2.88 million tug-of-war has broken out.

With the ink fresh on AFSCME District Council 33's contract, leaders of the smaller municipal union, District Council 47, are asking that their members receive the same signing bonus the 9,000 members of D.C. 33 received for ratifying their contract last week: $2,800.

That is $800 more than the bonus D.C. 47 negotiated for its members, about 3,600 white-collar employees, when they ratified their contract in March. D.C. 47's leader says the city promised everyone would get the same bonus.

The two unions, whose members went years without contracts or raises, negotiated similar deals: wage increases of 3.5 percent following ratification, plus an additional 2.5 percent in mid-2015. D.C. 47's contract lasts through 2017 and includes a 3 percent boost in 2016, while D.C. 33's ends that year. Increases in employees' contributions to their pension funds were also the same.

But D.C. 47 president Frederick Wright said his members deserve the same bonus as the other union.

"Our position is, we should get the $800," he said Monday.

When D.C. 47 ratified its contract, the Nutter administration's chief negotiator, Shannon D. Farmer, wrote to Wright outlining a mutual agreement that if its blue-collar counterpart ended up with a more favorable contract, the city would improve D.C. 47's package.

The letter said in part: "The city agrees that if . . . the city negotiates more favorable terms concerning wages, ratification lump sum bonuses, overtime or pensions with any other union . . . such terms will be applicable to the employees represented by District Council 47. . . ."

Farmer said Tuesday, "The intention was that [D.C. 47 members] wouldn't be economically disadvantaged from settling first."

The city says those members were not disadvantaged in the end - because they more than made up for the $800 by ratifying their deal in March, months before the larger union settled.

The administration's position is that members of D.C. 47 are not entitled to the additional $800, Nutter spokesman Mark McDonald said.

"If you look at what they got in wage increases and longevity and step increases during that time," McDonald said, "it's well more than $800."

The city's finance director, Rob Dubow, broke down the numbers this way:

The average D.C. 47 member salary was $35,373 when the union ratified. The initial 3.5 percent wage increase, plus about six months of longevity and step increases under the new contract, add up to an additional $941 on average per member.

Wright disagrees with the administration's logic.

"The bonus was separate, so we are going to fight it," he said. He said the union was already threatening to go to arbitration if it does not get the additional $800 for each member.

The D.C. 47 contract is expected to add $122 million to the city's costs. The D.C. 33 contract, overwhelmingly approved by its members last week, adds a projected $127 million.

When Wright did the math and saw the $2.88 million total - that's 3,600 times $800 - he said, "That's why they are trying to fight it."