Seems every time I try to use a disposable tube in my Stealth machines...the needle raises up on me when it exits the tip. I'm bending the shaft of the bar slightly, like you would in a Neuma, rubber bands are in the proper position (I know this because they're not breaking every 45 seconds anymore) , Im not running Balls Out...I don't understand why the needle flutters up and down no matter which brand I use, yet none of this happens when I use a stainless steel tube. Im sick to death of cleaning these things, 16 years is long enough. Anybody have any ideas?