The N.C. Utilities Commission has scheduled a Monday hearing to allow limited cross-examination of two witnesses in the Duke Energy-Progress Energy merger case.

The commission said Tuesday it will let the N.C. Waste Awareness and Reduction Network, a merger opponent, question an official of the commission’s Public Staff and a Progress vice president.

Both had submitted written testimony on the impacts of the utilities’ plans to boost competition for wholesale power after the merger, and on federal authorities’ conditional approval of the plan.

WARN contends that so much about the $26 billion deal has changed since September, when the commission held merger hearings, that more testimony is warranted. Changes to the merger plan could increase costs to N.C. utility customers, it has argued, including potential billions invested in nuclear plants.

The utilities and the Public Staff had argued Tuesday against more hearings.

The commission’s order gave WARN half a loaf, allowing the group to cross-examine the two witnesses but not letting it put on new testimony.

Duke and Progress hope to close the merger by July 1. It’s unclear whether the Monday hearing will derail that schedule.

“We’re pretty concerned that (the commission) is still on the utilities’ schedule instead of a reasonable schedule, and they’re trying to narrow the case,” said Jim Warren, WARN’s executive director. “But we’re clear that our concerns remain unaddressed, and that we think we’re right.”

Duke spokesman Tom Williams said the utilities “will continue to work toward our July 1 closing date.”

In a filing earlier Tuesday, Duke and Progress said WARN had raised issues that have already been addressed, are unrelated to any changes since September or are speculative events that would be covered by existing laws.

The utilities said “none of these comments justify any additional filings, testimony or hearings.”

WARN raised the possibility of utility customers being forced to pay for a share of the Summer nuclear plant under construction in South Carolina or billions to repair Progress’ Crystal River plant in Florida.

Duke has acknowledged potential interest in buying a share of Summer, but the utilities say such a move would be addressed in separate proceedings. A settlement agreement with consumer advocates says N.C. customers aren’t responsible for Progress’ liabilities in Florida, they add.

“The merger of the applicants, if approved, will do nothing to impair the commission’s ability to review and take appropriate action if and when any of the events of concern to NC WARN actually occur,” the utilities wrote.

The Federal Energy Regulatory Commission approved the merger, with conditions, on June 8. South Carolina’s utilities commission will rule only on the utilities’ plan to jointly control their power plants.