VICTORIA — Tucked inside a story out of New York this week was eyebrow-raising news about the B.C. Liberal government proposal to build a hydroelectric dam at Site C on the Peace River.

Premier Christy Clark, in the course of an interview with the Bloomberg news service, disclosed that the government was now looking at a cost estimate of $8.5 billion for the project, a number not previously shared with the B.C. public.

When I first saw the report late Wednesday afternoon, I wondered if New Yorkers had worked the exchange rate between Canadian and American dollars in the wrong direction.

For the B.C. Liberals had stubbornly defended a $7.9-billion budget figure for Site C through multiple expressions of doubt by critics and skeptics of every kind.

Officially, according to project proponent BC Hydro, the budget was “a bottom-up cost estimate based on the project’s upgraded design and detailed construction schedule, with updated market prices for labour, equipment and materials.”

Moreover, “an external peer review by KPMG determined both the process for developing the assumptions and the construction of the financial model used in the cost estimates were appropriate.”

Contingencies, interest during construction, an allowance for inflation — all were built in to the budget. Again and again, the Liberals insisted that the $7.9 billion was as solid as, well, a giant earthfill dam.

Would the premier really choose to revise the cost estimate by $600 million, several thousand kilometres and three time zones away from the folks who’ll be stuck with the already hefty tab for this megaproject?

Well, yes, as it turned out. That was precisely what she did.

Asking around late Wednesday, I was advised that the government had challenged Hydro for a revised cost accounting on the project, and Clark, being aware of the pending revision, had chosen to share the higher number with Bloomberg.

Later in the evening I caught up with Energy Minister Bill Bennett to ask what happened to change his take-it-to-the-bank figure of $7.9 billion.

Nothing, he insisted. That was still the baseline budget for the project. But the government had pressed Hydro for additional “scenarios” on Site C and it was the cost estimate for one of those scenarios that the premier cited.

I wondered what sort of scenarios. But Bennett insisted he could say no more. The matter was before cabinet. His oath of confidentiality had to take precedence.

So, as the day ended it looked as if the B.C. Liberals had announced a $600 million revision in the cost of the most expensive public project in provincial history, while offering zero explanation for the change.

There matters stood until Thursday afternoon when BC Hydro, prodded by my colleague Rob Shaw, responded with an explanation, such as it was.

“Government asked us to develop a cost estimate that would have greater contingencies for unforeseen costs such as higher-than-forecast inflation or interest rate fluctuations that are different than anticipated,” it said. “We can confirm that $8.5 billion is within the range of the revised cost estimate.”

Note the $8.5 billion is said to be “within the range,” suggesting a higher estimate might be forthcoming from the process of revision set in motion by the Liberals.