Sorry, if this is wrong forum, thanks for the info bout Sync, that's really help.
The case is if I have 128 BPM on Deck A and I want to mix with 134 BPM in Deck B. I usually use other DJ Software, they provide me with metronome, so I can set the metronome with 131BPM then use it as a beat anchor for Deck A (which is 128BPM) so Deck A will have new BPM 131. After syncing with Deck B (now deck B has 131BPM), I raise the metronome step by step until I got 134BPM. I use this if I want to change the music genre, from progressive house to Trance (which usually have BPM range around 130-140).
In mixvibes I use middle song to bridge the higher BPM, let's say I have 128bpm song and want to raise bpm to 135, I use song that have 130bpm or 132.
If I can edit (raise up or down the bpm song) using keyboard not using the pitch control (which I find so hard to get precise bpm like 130, 131, etc), I think this function will give mixvibes to the next level of solving case in DJ-ing problem..
Anyway thanks syIMV for your respond.