In Ableton Live, I’ve mapped the + (zoom in) and - (zoom out) keyboard keys to my "wheel up" and "wheel down" actions so that I can (finally!) use the mouse wheel to zoom in and out—a feature that is native in practically all other audio, photography, video and text apps yet inexplicably doesn't exist in Ableton. While the above mapping setup works, there is quite a bit of lag and unresponsive when doing so.
Meanwhile, using another mapping app called USB Overdrive, the zooming is extremely smooth and rapid. Likewise, on my Windows 7 machine, I have gone through the same process with a open-source program called autohotkey, and everything works perfectly there too (using the same mouse).
Therefore, am I doing something wrong or is this an issue with BetterTouchTool not refreshing quickly or smoothly enough? I attached a ZIP file showing the difference between zooming in and out using BetterTouchTool and USB Overdrive.