Cubase 8 Pro: TimeStretch and Audiowarp incompability?


I record guitar through an interface with direct input into Cubase 8 Pro. When parts are tricky to play, I like to record them in a slower tempo, edit them with Audiowarp so every note is in place and then TimeStretch them to the desired tempo.

I know that Audiowarp changes are discarded if you use TimeStretch directly, that’s why I use the render-in-place function on the tracks to permanently apply the changes before I do anything with the tempo.

Yet when I use TimeStretch on the rendered file (in which every note is perfectly in place) and look at the new waveform in the new tempo the transients are a little bit off the timing again. They sound in place but I can not be sure especially when the waveform looks as if it’s wrong.

-Does this have anything to do with the TimeStretch Algorithm you can use?
-Is there anything fundamental that I’m missing that I’m doing wrong here?
-Is there any way to apply audiowarp changes without rendering-in-place which makes a stereo track out of the mono track?