Four Greater Portland transit providers say they haven’t added their signatures to a letter freeing up $8 million in federal relief funding because of multiple errors in the document.

Officials at the four agencies have withheld their required signatures from the so-called “split letter,” which tells federal authorities how the money will be divvied up, delaying previously announced transit improvements and a half-price bus fare promotion through the end of the year.

The agencies said Monday that they haven’t signed because of problems with the letter’s wording, not because they seek to redirect funding approved in March by the policy board of the Portland Area Comprehensive Transportation System, or PACTS, the local planning agency that oversees federal transit funding.

“It should be stated again that we are not refraining from signing the split letter with the goal or intention of redirecting the funding allocation that was approved by the Policy Board,” top officials from Casco Bay Lines, the Northern New England Passenger Rail Authority, South Portland Bus Service and Biddeford-Saco-Old Orchard Beach wrote to PACTS officials on Friday.

The agencies said they want to see changes in the letter’s language and a review of the organization’s broader funding framework.

Chris Chop, the regional planning agency’s transportation director, said the funding formula was approved unanimously by the policy board more than a year ago. An accelerated review of the framework would be recommended in response to the agencies’ request, Chop said in a statement.

“We have always been committed to improving the decision-making process, and we welcome diverse perspectives,” Chop said. A PACTS policy board meeting next week will address funding and process questions.

The board voted narrowly to fund more than $7 million from the American Rescue Plan Act on improvements including faster bus routes, updated shelters and a half-price fare holiday. All but one regional transit agency voted against the measure because of disagreement over the funding application process and a desire to use more of the money to subsidize daily operations.

Before they will sign, the transit agencies said they want to resolve errors they have found in the split letter.

For example, $1.1 million for the half-price fare initiative was directed entirely to Greater Portland Metro bus service to be used in partnership with three other agencies, instead of the money being divided among the four as it should, officials said. Another $750,000 for bus shelter improvements and $380,000 for a multi-agency passenger information system also was not distributed accurately in the letter, they said.

The local agencies also took issue with a statement concluding the split letter that said the figures were developed comprehensively and collaboratively. Instead, funding allocations to Casco Bay, Biddeford-Saco-Old Orchard Beach and South Portland buses and the Downeaster “was arbitrarily developed by PACTS staff without collaboration from those agencies,” the officials wrote.

The funding framework used to distribute the relief money should be reviewed and updated to prevent similar problems with split letters and funding delays in the future, they added.

Friday’s letter is the first formal response from the four transit agencies to a tense confrontation over the American Rescue Plan Act funding package. The standoff has pitted the agencies against the leadership of PACTS and the Greater Portland Council of Governments, the planning group that oversees the regional transportation system.

In their letter, the four agencies said it was “concerning and questionable” that planning officials have resisted multiple requests for a public meeting to discuss the issues.

The mischaracterization of transit providers and questioning of their commitment to customers and the community by regional planning staff “continue to compromise the role of GPCOG/PACTS as an impartial regional facilitator,” the agencies wrote.

On May 10, the South Portland City Council heard arguments from staff as to why the city should cancel its paid membership in GPCOG and instead use the roughly $46,000 dues to retain a lawyer to protect its transit-related interests. Councilors have requested more information and discussion on the issue.