Dynamic analysis

Hi, 

I recently had to redo my whole collection becasue my harddrive on my laptop was goosed. Most of my tracks are modern, electronic stuff so it's not normally an issue, but I occassionally have to play some hip hop or 80s stuff, and when I have been analysing the second types of music, I use dynamic analysis, as it used to give me a variable reading of the BPM. Now, however, for some reason. it gives me a consistent BPM reading of the whole track, which makes it nigh on impossible to set any loops or to use the sync function.

Is this due to a change in how rekordbox operates, or is it simply that I'm doing something wrong? I was previously using verion 4.something, now I'm using verion 5.whateversthelatest.

Any help or advice would be greatly appreciated. 

Thanks