All transitions need extra frames in order to cover the transition length. The number of extra frames you need is determined by the length of the transition. You can, however, create your own handles by changing a clip’s in point and out point in the Viewer. Or you can do it in the timeline by taking the razor tool and cutting X number of frames from the beginning and end of the clip to cover the transition length. There are many ways to create handles in FCP. These are just 2 of them.
But if you’re in the unfortunate position that you need absolutely every last frame of edited audio to be audible then the answer is basically…..no. If you just need to do simple fade in/fade outs, you can do that using key frames and not have to worry about using a preset audio transition.
Hope this helps answer your question.
– Don