Does this explain it better?

If you were to offset your outgoing and incoming clips onto two separate tracks, as I have done here, you should be able to find 5 seconds before the transition centre point on the incoming clip, and 5 seconds after the transition on the outgoing clip.
If you cannot find those extra five seconds in each case, your transition cannot be the full 10 seconds long. The upshot of that is that you move your outgoing clip earlier on the timeline (shortening your overall sequence in the process). You can do this by ripple trimming either the head of the incoming clip or the tail of the outgoing clip as appropriate until you have the required 5 second handles.
Simon Ubsdell
tokyo productions
hawaiki