Rekordbox DJ / DDJ-RZ Sample BPM, change and sync?

When adding samples to my rekordbox dj, I can open a "edit" menu on each one.

1. In it it looks like I can add the tempo for each sample, but when marked with the mouse it automatically bounces off and is only automatically (and often wrong) detected. I have analyzed the sample and edited it in Rekordbox Export mode, but it still won't change the sample BPM. So - how can I make the rekordbox dj sampler change the BPM?

2. For the samples that ARE correctly analyzed, the "sync" function for tempo only works in loop-mode, and not in one shot-mode. Is it possible to sync the one-shots? This is really disturbing for vocal samples.

I use a Macbook Pro running Yosemite 10.5.

Thanks in advance!