misleading gold figures

Before putting forward this proposition, I will state that I am heavily into gold, having been accumulating almost exclusively for the past 2 years.

An issue which is becoming more concerning to me is the 'habit' of Australian gold miners quoting their cost of producing an ounce of gold (COP) in US$.
The reason for the concern is that who knows what exchange rate they are basing it on !
As the COP is for all intents & purposes a fixed cost that is incurred in A$, it is meaningless quoting it in US$ unless it is also accompaied by the exchange rate used at arriving at the US$ COP.

A difference between an exchange rate of $0.50 & $0.60 essentially wipes out the gain from gold rising from US$300 to US$350

All thats gold does not glitter