On the brink of approving a deal to join the region's newest 911 center, Dunwoody council members had one more presentation to sit through before the vote.

Councilman Danny Ross arrived armed with a DeKalb County police official, a PowerPoint presentation and a new set of numbers. He wasn't willing to concede that deliberations on the proposal were over yet.

"I didn't stop looking at this thing," Ross said. "I'm still not comfortable with the revenue side of this."

The Dunwoody City Council ultimately postponed a decision Monday night to strike a deal with ChatComm, the emergency operations center that currently serves Sandy Springs and Johns Creek. Ross' last-minute pitch to the council revealed revenues might run $200,000 less than expected, could cost more than $465,000 in additional expenses per year and open the possibility of worse response time for fire and EMS services.

By the end of the presentation and nearly another hour of discussion, the council members decided they weren't prepared to vote on the ChatComm agreement.

"I make my decisions with my calculator," councilman Doug Thompson said. "To me, clearly ChatComm is better. But from this standpoint, I don't think we can go forward."

Prior to the meeting, city officials and council members seemed poised to leave DeKalb's dispatch system and go with . Sandy Springs and Johns Creek launched ChatComm in September 2009 after years of frustration with the Fulton County system.

Those cities have lobbied Dunwoody to join the new center, hoping the addition of Dunwoody would cut their costs for subsidizing the center by about a third.

"Why are we in such a hurry to jump?" Shortal said. "We should take a closer look at this."