USD Currency with half cent

I'm needing to track fractions of cents in the USD field, for example, I have a rate of $0.065 however Sugar rounds this to $.07.  I've been unable to find a setting or anywhere in the forums with someone asking about this.  Anyone have any ideas?  I can always create a new field that is not USD and maybe that is the solution.  I'm using Professional 9.0.1

Thanks,

Brian