Printrbot Simple Metal Z-top Filament Guide

I found out that by having the filament rest on Z-axis bar while the printer is running tends to slack my Y-axis belt and ended up with printed part shifted to Y-positive direction on each layer. So I was thinking, why not using the Teflon tube so that no more load on Y-axis. The filament will be inserted on the bottom side of the mount and PTFE tube to guide the filament on the other end. This product is design to operate in conjunction with my other design: http://www.thingiverse.com/thing:601