House Democrats officially gained two and lost two on Thursday as they continued their painstaking zigzag toward 216 votes and final passage of a sweeping health care overhaul, now likely on Sunday.Leaders got two pieces of good news, with retiring Science and Technology Chairman Bart Gordon (D-Tenn.) and freshman Rep. Betsy Markey (D-Colo.), who voted "no" on the original House bill, announcing they would back reform this time around. But those gains were offset by the losses of Reps. Michael Arcuri (D-N.Y.) and Stephen Lynch (D-Mass.) who flipped their previous support to opposition.Lynch, in particular, was a blow to reform supporters, since the former union president had not been on any watch lists of potential vote flippers. He ripped the Senate-passed measure as a surrender to insurance companies, and he held fast to his opposition even after a meeting at the White House with President Barack Obama on Thursday afternoon.Though Obama failed to sway Lynch, House Democrats were buoyed by the whip in chiefs decision on Thursday to postpone his planned Asia jaunt until later this year so he can be on hand to help round up support for his signature domestic initiative.The release of the final bill text and estimates from the Congressional Budget Office gave handfuls of other undecided lawmakers some homework to do, as many on the fence continued to reserve judgment until reading through the language and scoring. But the CBOs deficit reduction projections a whopping $1.2 trillion in the second decade had some former opponents encouraged. The numbers sound promising, but I want to see how we got to the numbers, said Rep. Brian Baird (D-Wash.), who opposed the House-passed bill.The arithmetic for Democratic leaders is simple: If they can hold on to all 216 of the Democrats who voted for House passage and are still serving, they win. But rounding up those supporters has proved tricky. And they need to offset every defection by converting someone who voted against the original measure.Rules Chairwoman Louise Slaughter (D-N.Y.) dismissed the threat of minimal defections. Weve got a surplus. Weve got some spares, she said. Speaker Nancy Pelosi (D-Calif.) likewise projected confidence, telling reporters at a midday press conference, We feel very strong about where we are.Others were measured. Energy and Commerce Chairman Emeritus John Dingell (D-Mich.) said support for the legislation looks good and feels good. But the veteran health care reform advocate cautioned that this was the murkiest time in the vote-counting process.The gravest threat remains abortion language in the Senate version that some anti-abortion rights Democrats argue doesnt go far enough to block taxpayer dollars from funding the procedure. Rep. Bart Stupak (D-Mich.) has led opposition to the provision, but just how many lawmakers are behind him remains unclear, and leaders are hoping they can hold abortion-related defections down to about five.