Regarding the Sync functionality and BPM changing afterwards

Hey guys. So I took some time ti read the manual, but until I get to the relevant stuff I have to ask here:
It seems that after a beatmixing using the sync option, I can't use the controller to affect the song's tempo.
Example:
1. I start with a 100 BPM song. SONG A.
2. I want to mix in a 110 BPM song. SONG B.
3. I sync SONG B to SONG A, which means that SONG B goes from 110 BPM to 100 BPM.
4. I mix SONG B in, fade SONG A out. So far, so good.
5. Now, this is where the problem is. I want to get SONG B to its original tempo (from 100 to 110), BUT! gradually. I can't do it with the controller. The only way I can make it is to press in the software on the reset bpm button. But it is not gradual.
What can I do in order to be able to manipulate the song's bpm from the controller, after I have used the sync option? I tried to toggle on and of the "master" option, didn't help.
It seems that after a beatmixing using the sync option, I can't use the controller to affect the song's tempo.
Example:
1. I start with a 100 BPM song. SONG A.
2. I want to mix in a 110 BPM song. SONG B.
3. I sync SONG B to SONG A, which means that SONG B goes from 110 BPM to 100 BPM.
4. I mix SONG B in, fade SONG A out. So far, so good.
5. Now, this is where the problem is. I want to get SONG B to its original tempo (from 100 to 110), BUT! gradually. I can't do it with the controller. The only way I can make it is to press in the software on the reset bpm button. But it is not gradual.
What can I do in order to be able to manipulate the song's bpm from the controller, after I have used the sync option? I tried to toggle on and of the "master" option, didn't help.