the first beat should be solved by zooming in closer and listening. The other... learn to warp it manually if ableton screws up. It's good, but it still isn't perfect.

solution: don't warp the track.  seriously!  you know what bpm it is, you can push/pull the tempo by enabling the little button on the right hand side, "d" track delay, and dragging the values ( negative values in milliseconds > 0 > positive values in milliseconds), this is for plug-in delay compensation, but you can also nudge tracks with it for beatmatching believe it or not.  Unfortunately you can't map that midi yet, but you can use it like a non-pitch tempo adjust.
worst case scenario - warp the track and take your mouse and push/pull the 1:1 warp marker by dragging it left and right to compensate, a bit like steering a gigantic ship in a storm, but works in a pinch
there is a tiny little triangle that appears when you do this in the warp view, you can map that to midi with a little cunning. 
just my two cents which prob aren't worth that

I been doing this but thought it was a bit unorthadox. What i mean is i spend  time lining up my tracks then whn im in a mix i move the marker which means i then have to move the marker of the next incomming track and so on. Which kind of defeats the point of prepering tracks before hand. Id prefer to know that once ive used mixed a track that it will be ready for future use rather than having to keep shifting the marker!