Thursday afternoon, just five months after sitting down with embattled schools Chancellor Cathie Black, Downtown school advocates faced her replacement, Dennis Walcott. Yet again they laid out their urgent concerns over school crowding, but not before the new chancellor made an announcement that sweetened the tone of the occasion.

“I have good news,” Walcott told Assembly Speaker Sheldon Silver’s School School Overcrowding Task Force, a group of parents, principals and Downtown leaders.  “And that is that Peck Slip will become a reality.”

“Peck Slip,” the hoped-for elementary school near the South Street Seaport, had been a matter of lengthy real estate negotiations between the city and the U.S. Postal Service over vacated space in the post office building at Peck Slip and Pearl Street. Though no surprise, the announcement of the deal drew a rare response from this group of Department of Education critics towards a Department of Education official: Applause.

“This was a site that was identified by this task force and we advocated for it,” Silver said. “It’s great news for our task force, for our community and for our children.”

Still, the school advocates quickly pointed out to the chancellor that those 470 new seats—due to open in 2015—would be too little, and too late to make room for continuing kindergartner boom in Lower Manhattan.

Eric Greenleaf, the P.S. 234 parent whose demographic projections are often cited in discussions of Downtown school overcrowding, again recited the alarming numbers: By 2014, he said, there will be no school seats for about half the children entering kindergarten.

“As much as we appreciate Peck Slip we need to see some additional schools,” Greenleaf told Walcott. “And they need to be funded and sited as soon as possible.”

DOE officials have refuted Greenleaf’s demographic doomsday scenarios, but Walcott stopped short of saying he was wrong.

“Obviously there’s been some disagreement between the numbers you project and others may project as far as the birth rates and what we say,” Walcott said. “We want to look at the overlay of numbers and see where we have a discrepancy.”

That was a far different response than Greenleaf got from Cathie Black when, at the group’s meeting with her in January, she famously joked that birth control might be the solution to Downtown school overcrowding. Still, Greenleaf told the Trib after the meeting, that the “discrepancy” is 1,400 or 1,500 seats.

“Ultimately, the proof of the pudding is whether [Walcott] is willing to take the message that he hears down here, be convinced by it, and convey it to the people who need to hear it,” Greenleaf said. “Most importantly, the mayor.”

In the meantime, the task force would like to see more seats added to the Peck Slip school that Walcott now says is certain.

“Can we look at 600 seats in place of the 400?” asked Paul Hovitz, co-chair of CB1’s Youth and Education Committee.

“That’s part of future discussions,” Walcott replied. “Let’s just bask in the glow of the announcement.”