It's just rounded. Shown value is different form the actual value.
the 2nd is 0.0065 and the 1st is 0.013.
What evidence do you have for that?
Look at this USD fee:
1.98000000 ฿TC at $17.29000 (fee) $0.22220
By my calculations, at 0.65% - the fee should be $0.22252230
If they're rounding - it's not at a consistent number of DP for BTC compared to USD... and how the hell did they come up with 0.22220 anyway??
What makes you think it's a rounding for *display* and not a rounding of the underlying value?
Does/did mtgox have a displayed policy on how they round anyway?
Who told you the exchange rate was exactly $17.29 and has not been rounded? It's very hard to mess up an easy task like multiplying 2 numbers when you program.