In NSW, the police would charge you with low range PCA. Because of the low reading you may be able to plead not guilty and argue that your blood alcohol reading was less than 0.05 at the time of driving. I can explain the defence in a bit more detail if you are in NSW.
Thanks for your explanation - so the bottom line is you will get booked for blowing 0.05 - there is absolutely no leniancy in NSW. This was just a hypothetical question no further detail required.
The Victorian position is that the Act specifically includes .05 as being a positive reading. You would need a blood sample and a toxicologist to possibly read it down.