heads vs oppies

I'm just wondering what you all think about the heads vs oppies play at the moment??

As I speak, the heads are 14.5 (and possibly about to hit 15) and the oppies 5.6.

Now, lets say the heads hit 20c which is a given in the near future, that would be about a 25% increase. Should the heads be at 20c, the oppies should be around the 10-11c mark which would be about a 100% increase. With an expiry over 5 months away, i'm wondering why the current premium on the oppies isn't higher??

Thoughts?