The code says “exceeds eighty milligrams”, so if it were 100, I can't say what they would say, but there is a presumption of accuracy that would be challenged, I would presume, as you get lower. Often with defence counsel, the lower the BAC, the more you'll have to argue the presumption, which is that the machine was working correctly at that time.
On February 28th, 2008. See this statement in context.