Cannot add constant power that centres on cut, even though I have handles

Hey guys, 

I've been having this problem since there was an Adobe update a few months ago. Why can't I add a constant power inbetween my audio tracks? Both the clips have handles, there is quite a bit of space on either side, but Premiere is only allowing me to add the effect at the start of the cut. 

One hint seems to be that when I drag one of the clips forward a bit, Premiere allows me to add a constant power at the end of the clip that centres on cut. But then I am subsequently disallowed from adding a centre on cut at the beginning of the clip. 

These are clips with a lot of extra audio (handles) to work with on either side, so this doesn't make any sense. Someone please help me!