A Treasury analysis of the coalition's policies handed on Wednesday to the three independents - Bob Katter, Rob Oakeshott and Tony Windsor - found the costings out by between $A7 billion and $A11 billion.
"What this exercise proves is that we have absolutely nothing to hide and we are entering into these discussions in the fullest spirit of candour," Mr Abbott told reporters in Canberra.
But Treasurer Wayne Swan said the opposition had set out to "deliberately deceive" the Australian people.
Mr Windsor said the revelation makes him suspicious of the coalition, given its long refusal to submit its costings to Treasury, and he is seeking an explanation.
Shadow treasurer Joe Hockey said Mr Windsor was not available to hear that explanation from the coalition on Wednesday night.
"We have a difference of opinion with Treasury over nine or 10 different policies," he told ABC Radio.
The coalition submitted 301 policies to Treasury and got the tick on a vast amount of them, Mr Hockey said.
"The areas where we have a difference of opinion with the Treasury are specifically relating to the role of government," he said.
He said there were about $A5 billion worth of savings that Treasury had not taken into account.
But he said even Treasury conceded the savings would be made should the opposition come to office and have the power to make certain decisions.
Opposition finance spokesman Andrew Robb said one issue related to interest on the multibillion dollar borrowings for the national broadband network, with the opposition calculating a saving of $A2.4 billion over the next four years through cancelling the scheme.
While Treasury calculated that at $A1.5 billion, Mr Robb said the difference related to the interest rate that was used for the calculation.
Mr Abbott denied the analysis was a bad look for when he and his shadow ministers meet the independents on Thursday.
"I'm not going to debate perceptions ... because in the end, perceptions are in the eye of the beholder," Mr Abbott he said.
"The bottom line is that the coalition will deliver a healthier, stronger fiscal position ... I think that's a good look."
Mr Abbott said the coalition would deliver substantially larger surpluses than Labour despite the Treasury analysis.
"That is the bottom line of that discussion," he said.
Mr Abbott said talks with the independents would continue in good faith and he hoped to make them feel more confident about forming a stable and competent government.
But it seems unlikely the coalition will grant Mr Katter his wish of reintroducing tariffs to boost the agricultural industry.
"Bob quite rightly wants to do the right thing by the rural industries in rural Queensland.
"Now I want to do the right thing by the rural industries of north Queensland too," Mr Abbott said.
"I don't think we can turn back the clock but supporting and helping rural industries is part of the coalition's DNA and that will never change."
