Using CMTime without rounding?

Question

I'm writing an application that uses AVFoundation and CMTime. I have logged the values of my CMTime instances created using CMTimeMake(). This value seems to be rounded to the nearest integer. I need a CMTime instance with a precise value, without rounding.

I have seen the rounding constants in the CMTime reference:

enum {
   kCMTimeRoundingMethod_RoundHalfAwayFromZero = 1,
   kCMTimeRoundingMethod_RoundTowardZero = 2,
   kCMTimeRoundingMethod_RoundAwayFromZero = 3,
   kCMTimeRoundingMethod_QuickTime = 4,
   kCMTimeRoundingMethod_RoundTowardPositiveInfinity = 5,
   kCMTimeRoundingMethod_RoundTowardNegativeInfinity = 6,

   kCMTimeRoundingMethod_Default = kCMTimeRoundingMethod_RoundHalfAwayFromZero
};

There aren't any example of how I can control which of these strategies is applied to a CMTime instance? Or, if this isn't the right way, how can I extract a precise value from a CMTime instance?

---

Edit:

I have found and tested CMTIME_HAS_BEEN_ROUNDED(). I passed my CMTime instance to this function and it returns No (indicating that the value has not been rounded). So why am I losing precision?