The risks of a botched green energy scheme were downplayed by senior officials to an incoming minister, a public inquiry has heard.
A submission to the enterprise minister removed a "stark" warning on cost controls.
The Renewable Heat Incentive (RHI) scheme could cost Northern Ireland taxpayers £700m.
The scheme, set up in 2012, encouraged businesses to switch from fossil fuels to renewable sources to generate heat.
But in 2016, it emerged that claimants could effectively earn more money the more fuel they burned because the subsidies on offer for renewable fuels were far greater than the cost of the fuels themselves.
An independent inquiry into the RHI scandal was established in January 2017.
On Tuesday, the RHI Inquiry was told that language in a key submission to DUP Enterprise Minister Jonathan Bell of 8 July 2015 was watered down in a series of drafts.
The submission aimed to set out the problems in the scheme and the cost controls needed to address them.
An early version of the submission, which clearly stated the projected expenditure was twice the available budget, was amended to remove the cost controls warning.
A paragraph which suggested that a funding shortfall might have to be paid from other Enterprise spending commitments was also completely removed.
The inquiry was told that payments for 2015-16 were forecast at £23m, but the available budget was only £11.6m.
"We're £12m short and we don't know what effect that's going to have on our budget - that's the message that's not being found," said inquiry counsel Joseph Aiken.
The inquiry's chairman, Sir Patrick Coghlin, asked whether there had been an attempt to manipulate the language of the submission to cover up the true scale of the financial crisis.
"Did someone suggest that we can't possibly reveal how bad it has got?" he asked.
Witness Stuart Wightman, who was running the scheme in its latter stages, said he believed there was still some uncertainty about the budget.
He said officials still hoped they could draw down extra Treasury cash to cover the shortfall.
But Sir Patrick said by that stage senior figures in the department knew there was a question over the implications of an overspend.
He said the submission sent to Mr Bell worked up by senior officials in his department had given him a "false" impression of the situation.
Mr Aiken said had the submission been more "up front and frank", then delays in implementing the cost controls it contained might have been overcome.
It took some two months before the cost controls proposed in the July submission were signed off by the minister.
The cause of that delay and the allegations that there was political interference to drag it out, are two major areas of investigation for the inquiry.